diff --git a/Changes.md b/Changes.md
index 5113a1680f5..d1d2366a5e7 100644
--- a/Changes.md
+++ b/Changes.md
@@ -19,6 +19,7 @@ API
 ---
 
 - OptionalValuePlug : Added a new plug type that pairs an `enabled` BoolPlug with a `value` ValuePlug.
+- Shader : Added support for using OptionalValuePlug to represent optional parameters.
 
 1.3.0.0 (relative to 1.2.10.0)
 =======
diff --git a/python/GafferSceneTest/ShaderTest.py b/python/GafferSceneTest/ShaderTest.py
index f1c98f89fc7..721dfe268cf 100644
--- a/python/GafferSceneTest/ShaderTest.py
+++ b/python/GafferSceneTest/ShaderTest.py
@@ -429,5 +429,27 @@ def testSpline( self ) :
 		with self.assertRaisesRegex( RuntimeError, "n1.__outAttributes : Cannot support monotone cubic interpolation for splines with inputs, for plug n1.parameters.spline" ):
 			network = n1.attributes()["test:surface"]
 
+	def testOptionalParameter( self ) :
+
+		node = GafferSceneTest.TestShader( "n1" )
+		node["type"].setValue( "test:surface" )
+
+		shader = node.attributes()["test:surface"].outputShader()
+		self.assertNotIn( "optionalString", shader.parameters )
+
+		node["parameters"]["optionalString"]["enabled"].setValue( True )
+		shader = node.attributes()["test:surface"].outputShader()
+		self.assertIn( "optionalString", shader.parameters )
+		self.assertEqual( shader.parameters["optionalString"], IECore.StringData() )
+
+		node["parameters"]["optionalString"]["value"].setValue( "test" )
+		shader = node.attributes()["test:surface"].outputShader()
+		self.assertIn( "optionalString", shader.parameters )
+		self.assertEqual( shader.parameters["optionalString"], IECore.StringData( "test" ) )
+
+		node["parameters"]["optionalString"]["enabled"].setValue( False )
+		shader = node.attributes()["test:surface"].outputShader()
+		self.assertNotIn( "optionalString", shader.parameters )
+
 if __name__ == "__main__":
 	unittest.main()
diff --git a/src/GafferScene/Shader.cpp b/src/GafferScene/Shader.cpp
index 046e201c5d4..b3e0839e5f2 100644
--- a/src/GafferScene/Shader.cpp
+++ b/src/GafferScene/Shader.cpp
@@ -40,6 +40,7 @@
 #include "Gaffer/PlugAlgo.h"
 #include "Gaffer/Metadata.h"
 #include "Gaffer/NumericPlug.h"
+#include "Gaffer/OptionalValuePlug.h"
 #include "Gaffer/ScriptNode.h"
 #include "Gaffer/StringPlug.h"
 #include "Gaffer/SplinePlug.h"
@@ -1024,10 +1025,16 @@ void Shader::compute( Gaffer::ValuePlug *output, const Gaffer::Context *context
 
 void Shader::parameterHash( const Gaffer::Plug *parameterPlug, IECore::MurmurHash &h ) const
 {
-	const ValuePlug *vplug = IECore::runTimeCast<const ValuePlug>( parameterPlug );
-	if( vplug )
+	if( auto optionalValuePlug = IECore::runTimeCast<const OptionalValuePlug>( parameterPlug ) )
 	{
-		vplug->hash( h );
+		if( optionalValuePlug->enabledPlug()->getValue() )
+		{
+			optionalValuePlug->valuePlug()->hash( h );
+		}
+	}
+	else if( auto valuePlug = IECore::runTimeCast<const ValuePlug>( parameterPlug ) )
+	{
+		valuePlug->hash( h );
 	}
 	else
 	{
@@ -1037,7 +1044,18 @@ void Shader::parameterHash( const Gaffer::Plug *parameterPlug, IECore::MurmurHas
 
 IECore::DataPtr Shader::parameterValue( const Gaffer::Plug *parameterPlug ) const
 {
-	if( const Gaffer::ValuePlug *valuePlug = IECore::runTimeCast<const Gaffer::ValuePlug>( parameterPlug ) )
+	if( auto optionalValuePlug = IECore::runTimeCast<const OptionalValuePlug>( parameterPlug ) )
+	{
+		if( optionalValuePlug->enabledPlug()->getValue() )
+		{
+			return Gaffer::PlugAlgo::getValueAsData( optionalValuePlug->valuePlug() );
+		}
+		else
+		{
+			return nullptr;
+		}
+	}
+	else if( auto valuePlug = IECore::runTimeCast<const Gaffer::ValuePlug>( parameterPlug ) )
 	{
 		return Gaffer::PlugAlgo::getValueAsData( valuePlug );
 	}
diff --git a/src/GafferSceneTest/TestShader.cpp b/src/GafferSceneTest/TestShader.cpp
index bb8faac1129..011749b464b 100644
--- a/src/GafferSceneTest/TestShader.cpp
+++ b/src/GafferSceneTest/TestShader.cpp
@@ -37,6 +37,7 @@
 #include "GafferSceneTest/TestShader.h"
 
 #include "Gaffer/CompoundNumericPlug.h"
+#include "Gaffer/OptionalValuePlug.h"
 #include "Gaffer/StringPlug.h"
 #include "Gaffer/SplinePlug.h"
 
@@ -59,6 +60,7 @@ TestShader::TestShader( const std::string &name )
 	parametersPlug()->addChild( new IntPlug( "i" ) );
 	parametersPlug()->addChild( new Color3fPlug( "c" ) );
 	parametersPlug()->addChild( new SplinefColor3fPlug( "spline" ) );
+	parametersPlug()->addChild( new OptionalValuePlug( "optionalString", new Gaffer::StringPlug() ) );
 }
 
 TestShader::~TestShader()