diff --git a/src/Constants.php b/src/Constants.php
index b1155343..aba799ba 100644
--- a/src/Constants.php
+++ b/src/Constants.php
@@ -52,6 +52,11 @@ class Constants extends \SimpleSAML\SAML2\Constants
      */
     public const NS_SEC_UTIL = 'http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd';
 
+    /**
+     * The namespace for the Metadata Exchange protocol.
+     */
+    public const NS_METADATA_EXCHANGE = 'http://schemas.xmlsoap.org/ws/2004/09/mex';
+
     /**
      * The schema-defined wsa fault codes
      */
diff --git a/src/XML/wst/AbstractBinaryExchangeType.php b/src/XML/wst/AbstractBinaryExchangeType.php
index 0c16de65..a49d4570 100644
--- a/src/XML/wst/AbstractBinaryExchangeType.php
+++ b/src/XML/wst/AbstractBinaryExchangeType.php
@@ -22,7 +22,7 @@ abstract class AbstractBinaryExchangeType extends AbstractWstElement
     use ExtendableAttributesTrait;
     use StringElementTrait;
 
-    /** @var string|\SimpleSAML\XML\XsNamespace */
+    /** The namespace-attribute for the xs:anyAttribute element */
     public const XS_ANY_ATTR_NAMESPACE = NS::OTHER;
 
 
diff --git a/src/XML/wsx/AbstractWsxElement.php b/src/XML/wsx/AbstractWsxElement.php
new file mode 100644
index 00000000..106a2185
--- /dev/null
+++ b/src/XML/wsx/AbstractWsxElement.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use SimpleSAML\WSSecurity\Constants as C;
+use SimpleSAML\XML\AbstractElement;
+
+/**
+ * Abstract class to be implemented by all the classes in this namespace
+ *
+ * @package tvdijen/ws-security
+ */
+abstract class AbstractWsxElement extends AbstractElement
+{
+    /** @var string */
+    public const NS = C::NS_METADATA_EXCHANGE;
+
+    /** @var string */
+    public const NS_PREFIX = 'wsx';
+}
diff --git a/src/XML/wsx/Dialect.php b/src/XML/wsx/Dialect.php
new file mode 100644
index 00000000..6321ac89
--- /dev/null
+++ b/src/XML/wsx/Dialect.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use SimpleSAML\XML\URIElementTrait;
+
+/**
+ * An Dialect element
+ *
+ * @package tvdijen/ws-security
+ */
+final class Dialect extends AbstractWsxElement
+{
+    use URIElementTrait;
+
+
+    /**
+     * @param string $content
+     */
+    public function __construct(string $content)
+    {
+        $this->setContent($content);
+    }
+}
diff --git a/src/XML/wsx/GetMetadata.php b/src/XML/wsx/GetMetadata.php
new file mode 100644
index 00000000..b1e67872
--- /dev/null
+++ b/src/XML/wsx/GetMetadata.php
@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\TooManyElementsException;
+use SimpleSAML\XML\ExtendableAttributesTrait;
+use SimpleSAML\XML\XsNamespace as NS;
+
+use function array_pop;
+
+/**
+ * Class defining the GetMetadata element
+ *
+ * @package tvdijen/ws-security
+ */
+final class GetMetadata extends AbstractWsxElement
+{
+    use ExtendableAttributesTrait;
+
+    /** The namespace-attribute for the xs:anyAttribute element */
+    public const XS_ANY_ATTR_NAMESPACE = NS::OTHER;
+
+
+    /**
+     * GetMetadata constructor
+     *
+     * @param \SimpleSAML\WSSecurity\XML\wsx\Dialect|null $dialect
+     * @param \SimpleSAML\WSSecurity\XML\wsx\Identifier|null $identifier
+     * @param array<\SimpleSAML\XML\Attribute> $namespacedAttributes
+     */
+    final public function __construct(
+        protected ?Dialect $dialect = null,
+        protected ?Identifier $identifier = null,
+        array $namespacedAttributes = []
+    ) {
+        $this->setAttributesNS($namespacedAttributes);
+    }
+
+
+    /**
+     * Get the dialect property.
+     *
+     * @return \SimpleSAML\WSSecurity\XML\wsx\Dialect|null
+     */
+    public function getDialect(): ?Dialect
+    {
+        return $this->dialect;
+    }
+
+
+    /**
+     * Get the identifier property.
+     *
+     * @return \SimpleSAML\WSSecurity\XML\wsx\Identifier|null
+     */
+    public function getIdentifier(): ?Identifier
+    {
+        return $this->identifier;
+    }
+
+
+    /**
+     * Test if an object, at the state it's in, would produce an empty XML-element
+     *
+     * @return bool
+     */
+    public function isEmptyElement(): bool
+    {
+        return empty($this->getDialect())
+            && empty($this->getIdentifier())
+            && empty($this->getAttributesNS());
+    }
+
+
+    /**
+     * Create an instance of this object from its XML representation.
+     *
+     * @param \DOMElement $xml
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
+
+        $dialect = Dialect::getChildrenOfClass($xml);
+        Assert::maxCount($dialect, 1, TooManyElementsException::class);
+
+        $identifier = Identifier::getChildrenOfClass($xml);
+        Assert::maxCount($identifier, 1, TooManyElementsException::class);
+
+        return new static(
+            array_pop($dialect),
+            array_pop($identifier),
+            self::getAttributesNSFromXML($xml),
+        );
+    }
+
+
+    /**
+     * Add this GetMetadata to an XML element.
+     *
+     * @param \DOMElement $parent The element we should append this GetMetadata to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = parent::instantiateParentElement($parent);
+
+        $this->getDialect()?->toXML($e);
+        $this->getIdentifier()?->toXML($e);
+
+        foreach ($this->getAttributesNS() as $attr) {
+            $attr->toXML($e);
+        }
+
+        return $e;
+    }
+}
diff --git a/src/XML/wsx/Identifier.php b/src/XML/wsx/Identifier.php
new file mode 100644
index 00000000..f28b286d
--- /dev/null
+++ b/src/XML/wsx/Identifier.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use SimpleSAML\XML\URIElementTrait;
+
+/**
+ * An Identifier element
+ *
+ * @package tvdijen/ws-security
+ */
+final class Identifier extends AbstractWsxElement
+{
+    use URIElementTrait;
+
+
+    /**
+     * @param string $content
+     */
+    public function __construct(string $content)
+    {
+        $this->setContent($content);
+    }
+}
diff --git a/src/XML/wsx/Location.php b/src/XML/wsx/Location.php
new file mode 100644
index 00000000..d3b9e67b
--- /dev/null
+++ b/src/XML/wsx/Location.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use SimpleSAML\XML\URIElementTrait;
+
+/**
+ * An Location element
+ *
+ * @package tvdijen/ws-security
+ */
+final class Location extends AbstractWsxElement
+{
+    use URIElementTrait;
+
+
+    /**
+     * @param string $content
+     */
+    public function __construct(string $content)
+    {
+        $this->setContent($content);
+    }
+}
diff --git a/src/XML/wsx/Metadata.php b/src/XML/wsx/Metadata.php
new file mode 100644
index 00000000..5ed17ace
--- /dev/null
+++ b/src/XML/wsx/Metadata.php
@@ -0,0 +1,132 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\ExtendableAttributesTrait;
+use SimpleSAML\XML\ExtendableElementTrait;
+use SimpleSAML\XML\XsNamespace as NS;
+
+/**
+ * Class defining the Metadata element
+ *
+ * @package tvdijen/ws-security
+ */
+final class Metadata extends AbstractWsxElement
+{
+    use ExtendableAttributesTrait;
+    use ExtendableElementTrait;
+
+    /** The namespace-attribute for the xs:any element */
+    public const XS_ANY_ELT_NAMESPACE = NS::OTHER;
+
+    /** The namespace-attribute for the xs:anyAttribute element */
+    public const XS_ANY_ATTR_NAMESPACE = NS::OTHER;
+
+
+    /**
+     * Metadata constructor
+     *
+     * @param array<\SimpleSAML\WSSecurity\XML\wsx\MetadataSection> $metadataSection
+     * @param array<\SimpleSAML\XML\SerializableElementInterface> $children
+     * @param array<\SimpleSAML\XML\Attribute> $namespacedAttributes
+     */
+    final public function __construct(
+        protected array $metadataSection = [],
+        array $children = [],
+        array $namespacedAttributes = []
+    ) {
+        $this->setElements($children);
+        $this->setAttributesNS($namespacedAttributes);
+    }
+
+
+    /**
+     * Get the child property.
+     *
+     * @return array<\SimpleSAML\WSSecurity\XML\wsx\MetadataSection>
+     */
+    public function getMetadataSection(): array
+    {
+        return $this->metadataSection;
+    }
+
+
+    /**
+     * Test if an object, at the state it's in, would produce an empty XML-element
+     *
+     * @return bool
+     */
+    public function isEmptyElement(): bool
+    {
+        return empty($this->getMetadataSection())
+            && empty($this->getElements())
+            && empty($this->getAttributesNS());
+    }
+
+
+    /**
+     * Create an instance of this object from its XML representation.
+     *
+     * @param \DOMElement $xml
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
+
+        $children = [];
+        foreach ($xml->childNodes as $child) {
+            if (!($child instanceof DOMElement)) {
+                continue;
+            } elseif ($child->namespaceURI === static::NS) {
+                continue;
+            }
+
+            $children[] = new Chunk($child);
+        }
+
+        return new static(
+            MetadataSection::getChildrenOfClass($xml),
+            $children,
+            self::getAttributesNSFromXML($xml),
+        );
+    }
+
+
+    /**
+     * Add this Metadata to an XML element.
+     *
+     * @param \DOMElement $parent The element we should append this Metadata to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = parent::instantiateParentElement($parent);
+
+        foreach ($this->getMetadataSection() as $metadataSection) {
+            $metadataSection->toXML($e);
+        }
+
+        foreach ($this->getElements() as $elt) {
+            if (!$elt->isEmptyElement()) {
+                $elt->toXML($e);
+            }
+        }
+
+        foreach ($this->getAttributesNS() as $attr) {
+            $attr->toXML($e);
+        }
+
+        return $e;
+    }
+}
diff --git a/src/XML/wsx/MetadataReference.php b/src/XML/wsx/MetadataReference.php
new file mode 100644
index 00000000..9d143941
--- /dev/null
+++ b/src/XML/wsx/MetadataReference.php
@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingElementException;
+use SimpleSAML\XML\ExtendableElementTrait;
+use SimpleSAML\XML\XsNamespace as NS;
+
+/**
+ * Class defining the MetadataReference element
+ *
+ * @package tvdijen/ws-security
+ */
+final class MetadataReference extends AbstractWsxElement
+{
+    use ExtendableElementTrait;
+
+    /** The namespace-attribute for the xs:any element */
+    public const XS_ANY_ELT_NAMESPACE = NS::OTHER;
+
+
+    /**
+     * MetadataReference constructor
+     *
+     * @param \SimpleSAML\XML\SerializableElementInterface[] $children
+     */
+    final public function __construct(
+        array $children = []
+    ) {
+        Assert::minCount($children, 1, MissingElementException::class);
+        $this->setElements($children);
+    }
+
+
+    /**
+     * Create an instance of this object from its XML representation.
+     *
+     * @param \DOMElement $xml
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
+
+        $children = [];
+        foreach ($xml->childNodes as $child) {
+            if (!($child instanceof DOMElement)) {
+                continue;
+            } elseif ($child->namespaceURI === static::NS) {
+                continue;
+            }
+
+            $children[] = new Chunk($child);
+        }
+
+        return new static($children);
+    }
+
+
+    /**
+     * Add this MetadataReference to an XML element.
+     *
+     * @param \DOMElement $parent The element we should append this MetadataReference to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = parent::instantiateParentElement($parent);
+
+        foreach ($this->getElements() as $child) {
+            if (!$child->isEmptyElement()) {
+                $child->toXML($e);
+            }
+        }
+
+        return $e;
+    }
+}
diff --git a/src/XML/wsx/MetadataSection.php b/src/XML/wsx/MetadataSection.php
new file mode 100644
index 00000000..706414ec
--- /dev/null
+++ b/src/XML/wsx/MetadataSection.php
@@ -0,0 +1,155 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\WSSecurity\XML\wsx;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingElementException;
+use SimpleSAML\XML\Exception\TooManyElementsException;
+use SimpleSAML\XML\ExtendableAttributesTrait;
+use SimpleSAML\XML\SerializableElementInterface;
+use SimpleSAML\XML\XsNamespace as NS;
+
+use function array_pop;
+
+/**
+ * Class defining the MetadataSection element
+ *
+ * @package tvdijen/ws-security
+ */
+final class MetadataSection extends AbstractWsxElement
+{
+    use ExtendableAttributesTrait;
+
+    /** The namespace-attribute for the xs:anyAttribute element */
+    public const XS_ANY_ATTR_NAMESPACE = NS::OTHER;
+
+
+    /**
+     * MetadataSection constructor
+     *
+     * @param (\SimpleSAML\XML\SerializableElementInterface|
+     *         \SimpleSAML\WSSecurity\XML\wsx\MetadataReference|
+     *         \SimpleSAML\WSSecurity\XML\wsx\Location) $child
+     * @param string $Dialect
+     * @param string|null $Identifier
+     * @param array<\SimpleSAML\XML\Attribute> $namespacedAttributes
+     */
+    final public function __construct(
+        protected SerializableElementInterface|MetadataReference|Location $child,
+        protected string $Dialect,
+        protected ?string $Identifier = null,
+        array $namespacedAttributes = []
+    ) {
+        Assert::validURI($Dialect);
+        Assert::nullOrValidURI($Identifier);
+
+        $this->setAttributesNS($namespacedAttributes);
+    }
+
+
+    /**
+     * Get the child property.
+     *
+     * @return (\SimpleSAML\XML\SerializableElementInterface|
+     *         \SimpleSAML\WSSecurity\XML\wsx\MetadataReference|
+     *         \SimpleSAML\WSSecurity\XML\wsx\Location)
+     */
+    public function getChild(): SerializableElementInterface|MetadataReference|Location
+    {
+        return $this->child;
+    }
+
+
+    /**
+     * Get the Dialect property.
+     *
+     * @return string
+     */
+    public function getDialect(): string
+    {
+        return $this->Dialect;
+    }
+
+
+    /**
+     * Get the Identifier property.
+     *
+     * @return string|null
+     */
+    public function getIdentifier(): ?string
+    {
+        return $this->Identifier;
+    }
+
+
+    /**
+     * Create an instance of this object from its XML representation.
+     *
+     * @param \DOMElement $xml
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
+
+        $children = [];
+        foreach ($xml->childNodes as $child) {
+            if (!($child instanceof DOMElement)) {
+                continue;
+            } elseif ($child->namespaceURI === static::NS) {
+                if ($child->localName === 'MetadataReference') {
+                    $children[] = MetadataReference::fromXML($child);
+                } elseif ($child->localName === 'Location') {
+                    $children[] = Location::fromXML($child);
+                }
+                continue;
+            }
+
+            $children[] = new Chunk($child);
+        }
+
+        Assert::minCount($children, 1, MissingElementException::class);
+        Assert::maxCount($children, 1, TooManyElementsException::class);
+
+        return new static(
+            array_pop($children),
+            self::getAttribute($xml, 'Dialect'),
+            self::getOptionalAttribute($xml, 'Identifier', null),
+            self::getAttributesNSFromXML($xml),
+        );
+    }
+
+
+    /**
+     * Add this MetadataSection to an XML element.
+     *
+     * @param \DOMElement $parent The element we should append this MetadataSection to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = parent::instantiateParentElement($parent);
+        $e->setAttribute('Dialect', $this->getDialect());
+
+        if ($this->getIdentifier() !== null) {
+            $e->setAttribute('Identifier', $this->getIdentifier());
+        }
+
+        $this->getChild()->toXML($e);
+
+        foreach ($this->getAttributesNS() as $attr) {
+            $attr->toXML($e);
+        }
+
+        return $e;
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/DialectTest.php b/tests/WSSecurity/XML/wsx/DialectTest.php
new file mode 100644
index 00000000..f6ed722f
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/DialectTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\Test\WSSecurity\Constants as C;
+use SimpleSAML\WSSecurity\XML\wsx\Dialect;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+
+/**
+ * Class \SimpleSAML\WSSecurity\XML\wsx\DialectTest
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\Dialect
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ *
+ * @package tvdijen/ws-security
+ */
+final class DialectTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$testedClass = Dialect::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_Dialect.xml',
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating a Dialect object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $dialect = new Dialect(C::NAMESPACE);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($dialect),
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/GetMetadataTest.php b/tests/WSSecurity/XML/wsx/GetMetadataTest.php
new file mode 100644
index 00000000..f804f286
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/GetMetadataTest.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\WSSecurity\XML\wsx\Dialect;
+use SimpleSAML\WSSecurity\XML\wsx\GetMetadata;
+use SimpleSAML\WSSecurity\XML\wsx\Identifier;
+use SimpleSAML\XML\Attribute;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * Tests for wsx:GetMetadata.
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\GetMetadata
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ * @package tvdijen/ws-security
+ */
+final class GetMetadataTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$testedClass = GetMetadata::class;
+
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$xmlRepresentation = DOMDocumentFactory::FromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_GetMetadata.xml'
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating an GetMetadata object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $attr1 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'attr1', 'testval1');
+
+        $getMetadata = new GetMetadata(
+            new Dialect('urn:x-simplesamlphp:namespace'),
+            new Identifier('urn:x-simplesamlphp:namespace'),
+            [$attr1],
+        );
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($getMetadata)
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/IdentifierTest.php b/tests/WSSecurity/XML/wsx/IdentifierTest.php
new file mode 100644
index 00000000..f1a487d1
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/IdentifierTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\Test\WSSecurity\Constants as C;
+use SimpleSAML\WSSecurity\XML\wsx\Identifier;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+
+/**
+ * Class \SimpleSAML\WSSecurity\XML\wsx\IdentifierTest
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\Identifier
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ *
+ * @package tvdijen/ws-security
+ */
+final class IdentifierTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$testedClass = Identifier::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_Identifier.xml',
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating a Identifier object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $identifier = new Identifier(C::NAMESPACE);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($identifier),
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/LocationTest.php b/tests/WSSecurity/XML/wsx/LocationTest.php
new file mode 100644
index 00000000..7fb867e6
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/LocationTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\Test\WSSecurity\Constants as C;
+use SimpleSAML\WSSecurity\XML\wsx\Location;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+
+/**
+ * Class \SimpleSAML\WSSecurity\XML\wsx\LocationTest
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\Location
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ *
+ * @package tvdijen/ws-security
+ */
+final class LocationTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$testedClass = Location::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_Location.xml',
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating a Location object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $location = new Location(C::NAMESPACE);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($location),
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/MetadataReferenceTest.php b/tests/WSSecurity/XML/wsx/MetadataReferenceTest.php
new file mode 100644
index 00000000..47e2089e
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/MetadataReferenceTest.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use DOMElement;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\WSSecurity\XML\wsa\Address;
+use SimpleSAML\WSSecurity\XML\wsa\EndpointReference;
+use SimpleSAML\WSSecurity\XML\wsx\MetadataReference;
+use SimpleSAML\XML\Attribute;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * Tests for wsx:MetadataReference.
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\MetadataReference
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ * @package tvdijen/ws-security
+ */
+final class MetadataReferenceTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+    /** @var \DOMElement $referenceParametersContent */
+    protected static DOMElement $referenceParametersContent;
+
+    /** @var \DOMElement $metadataContent */
+    protected static DOMElement $metadataContent;
+
+    /** @var \DOMElement $customContent */
+    protected static DOMElement $customContent;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$testedClass = MetadataReference::class;
+
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$xmlRepresentation = DOMDocumentFactory::FromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_MetadataReference.xml'
+        );
+
+        self::$customContent = DOMDocumentFactory::fromString(
+            '<ssp:Chunk xmlns:ssp="urn:x-simplesamlphp:namespace">SomeChunk</ssp:Chunk>'
+        )->documentElement;
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating an MetadataReference object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $attr1 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'test1', 'value1');
+        $attr2 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'test2', 'value2');
+
+        $chunk = new Chunk(self::$customContent);
+
+        $endpointReference = new EndpointReference(
+            new Address('https://login.microsoftonline.com/login.srf', [$attr2]),
+            [],
+            [],
+            [$chunk],
+            [$attr1],
+        );
+
+        $metadataReference = new MetadataReference([$endpointReference]);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($metadataReference)
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/MetadataSectionTest.php b/tests/WSSecurity/XML/wsx/MetadataSectionTest.php
new file mode 100644
index 00000000..415812ae
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/MetadataSectionTest.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\WSSecurity\XML\wsx\Location;
+use SimpleSAML\WSSecurity\XML\wsx\MetadataSection;
+use SimpleSAML\XML\Attribute;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * Tests for wsx:MetadataSection.
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\MetadataSection
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ * @package tvdijen/ws-security
+ */
+final class MetadataSectionTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$testedClass = MetadataSection::class;
+
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$xmlRepresentation = DOMDocumentFactory::FromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_MetadataSection.xml'
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating an MetadataSection object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $attr1 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'attr1', 'testval1');
+
+        $metadataSection = new MetadataSection(
+            new Location('urn:x-simplesamlphp:namespace'),
+            'urn:x-simplesamlphp:namespace',
+            'urn:x-simplesamlphp:namespace',
+            [$attr1],
+        );
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($metadataSection)
+        );
+    }
+}
diff --git a/tests/WSSecurity/XML/wsx/MetadataTest.php b/tests/WSSecurity/XML/wsx/MetadataTest.php
new file mode 100644
index 00000000..07513947
--- /dev/null
+++ b/tests/WSSecurity/XML/wsx/MetadataTest.php
@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\WSSecurity\XML\wsx;
+
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\WSSecurity\XML\wsx\Location;
+use SimpleSAML\WSSecurity\XML\wsx\Metadata;
+use SimpleSAML\WSSecurity\XML\wsx\MetadataSection;
+use SimpleSAML\XML\Attribute;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * Tests for wsx:Metadata.
+ *
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\Metadata
+ * @covers \SimpleSAML\WSSecurity\XML\wsx\AbstractWsxElement
+ * @package tvdijen/ws-security
+ */
+final class MetadataTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$testedClass = Metadata::class;
+
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/MetadataExchange.xsd';
+
+        self::$xmlRepresentation = DOMDocumentFactory::FromFile(
+            dirname(__FILE__, 4) . '/resources/xml/wsx_Metadata.xml'
+        );
+    }
+
+
+    // test marshalling
+
+
+    /**
+     * Test creating an Metadata object from scratch.
+     */
+    public function testMarshalling(): void
+    {
+        $attr1 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'attr1', 'testval1');
+        $attr2 = new Attribute('urn:x-simplesamlphp:namespace', 'ssp', 'attr2', 'testval2');
+
+        $child = DOMDocumentFactory::fromString(
+            '<ssp:Chunk xmlns:ssp="urn:x-simplesamlphp:namespace">Some</ssp:Chunk>',
+        );
+
+        $metadataSection = new MetadataSection(
+            new Location('urn:x-simplesamlphp:namespace'),
+            'urn:x-simplesamlphp:namespace',
+            'urn:x-simplesamlphp:namespace',
+            [$attr2],
+        );
+
+        $metadata = new Metadata([$metadataSection], [new Chunk($child->documentElement)], [$attr1]);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($metadata)
+        );
+    }
+
+
+    /**
+     */
+    public function testMarshallingEmpty(): void
+    {
+        $metadata = new Metadata();
+
+        $this->assertTrue($metadata->isEmptyElement());
+    }
+}
diff --git a/tests/resources/xml/wsx_Dialect.xml b/tests/resources/xml/wsx_Dialect.xml
new file mode 100644
index 00000000..3ffcdf11
--- /dev/null
+++ b/tests/resources/xml/wsx_Dialect.xml
@@ -0,0 +1 @@
+<wsx:Dialect xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex">urn:x-simplesamlphp:namespace</wsx:Dialect>
diff --git a/tests/resources/xml/wsx_GetMetadata.xml b/tests/resources/xml/wsx_GetMetadata.xml
new file mode 100644
index 00000000..f28a0f78
--- /dev/null
+++ b/tests/resources/xml/wsx_GetMetadata.xml
@@ -0,0 +1,4 @@
+<wsx:GetMetadata xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex" xmlns:ssp="urn:x-simplesamlphp:namespace" ssp:attr1="testval1">
+  <wsx:Dialect>urn:x-simplesamlphp:namespace</wsx:Dialect>
+  <wsx:Identifier>urn:x-simplesamlphp:namespace</wsx:Identifier>
+</wsx:GetMetadata>
diff --git a/tests/resources/xml/wsx_Identifier.xml b/tests/resources/xml/wsx_Identifier.xml
new file mode 100644
index 00000000..39651b91
--- /dev/null
+++ b/tests/resources/xml/wsx_Identifier.xml
@@ -0,0 +1 @@
+<wsx:Identifier xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex">urn:x-simplesamlphp:namespace</wsx:Identifier>
diff --git a/tests/resources/xml/wsx_Location.xml b/tests/resources/xml/wsx_Location.xml
new file mode 100644
index 00000000..b4a0d7e9
--- /dev/null
+++ b/tests/resources/xml/wsx_Location.xml
@@ -0,0 +1 @@
+<wsx:Location xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex">urn:x-simplesamlphp:namespace</wsx:Location>
diff --git a/tests/resources/xml/wsx_Metadata.xml b/tests/resources/xml/wsx_Metadata.xml
new file mode 100644
index 00000000..749d26bc
--- /dev/null
+++ b/tests/resources/xml/wsx_Metadata.xml
@@ -0,0 +1,6 @@
+<wsx:Metadata xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex" xmlns:ssp="urn:x-simplesamlphp:namespace" ssp:attr1="testval1">
+  <wsx:MetadataSection Dialect="urn:x-simplesamlphp:namespace" Identifier="urn:x-simplesamlphp:namespace" ssp:attr2="testval2">
+    <wsx:Location>urn:x-simplesamlphp:namespace</wsx:Location>
+  </wsx:MetadataSection>
+  <ssp:Chunk>Some</ssp:Chunk>
+</wsx:Metadata>
diff --git a/tests/resources/xml/wsx_MetadataReference.xml b/tests/resources/xml/wsx_MetadataReference.xml
new file mode 100644
index 00000000..25972d9c
--- /dev/null
+++ b/tests/resources/xml/wsx_MetadataReference.xml
@@ -0,0 +1,6 @@
+<wsx:MetadataReference xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex">
+  <wsa:EndpointReference xmlns:wsa="http://www.w3.org/2005/08/addressing" xmlns:ssp="urn:x-simplesamlphp:namespace" ssp:test1="value1">
+    <wsa:Address ssp:test2="value2">https://login.microsoftonline.com/login.srf</wsa:Address>
+    <ssp:Chunk>SomeChunk</ssp:Chunk>
+  </wsa:EndpointReference>
+</wsx:MetadataReference>
diff --git a/tests/resources/xml/wsx_MetadataSection.xml b/tests/resources/xml/wsx_MetadataSection.xml
new file mode 100644
index 00000000..79982e62
--- /dev/null
+++ b/tests/resources/xml/wsx_MetadataSection.xml
@@ -0,0 +1,3 @@
+<wsx:MetadataSection xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex" xmlns:ssp="urn:x-simplesamlphp:namespace" Dialect="urn:x-simplesamlphp:namespace" Identifier="urn:x-simplesamlphp:namespace" ssp:attr1="testval1">
+  <wsx:Location>urn:x-simplesamlphp:namespace</wsx:Location>
+</wsx:MetadataSection>