diff --git a/src/Illuminate/Database/Eloquent/Builder.php b/src/Illuminate/Database/Eloquent/Builder.php
index 8ab8e055e77f..058a7a528f8d 100755
--- a/src/Illuminate/Database/Eloquent/Builder.php
+++ b/src/Illuminate/Database/Eloquent/Builder.php
@@ -89,6 +89,9 @@ class Builder implements BuilderContract
     /**
      * The methods that should be returned from query builder.
      *
+     * Note that the names in the array need to be lowercase so that PHP's case-insensitivity
+     * regarding method calls can be achieved when forwarding the call to the base object.
+     *
      * @var string[]
      */
     protected $passthru = [
@@ -97,29 +100,29 @@ class Builder implements BuilderContract
         'avg',
         'count',
         'dd',
-        'ddRawSql',
-        'doesntExist',
-        'doesntExistOr',
+        'ddrawsql',
+        'doesntexist',
+        'doesntexistor',
         'dump',
-        'dumpRawSql',
+        'dumprawsql',
         'exists',
-        'existsOr',
+        'existsor',
         'explain',
-        'getBindings',
-        'getConnection',
-        'getGrammar',
+        'getbindings',
+        'getconnection',
+        'getgrammar',
         'implode',
         'insert',
-        'insertGetId',
-        'insertOrIgnore',
-        'insertUsing',
+        'insertgetid',
+        'insertorignore',
+        'insertusing',
         'max',
         'min',
         'raw',
-        'rawValue',
+        'rawvalue',
         'sum',
-        'toSql',
-        'toRawSql',
+        'tosql',
+        'torawsql',
     ];
 
     /**
@@ -1964,7 +1967,7 @@ public function __call($method, $parameters)
             return $this->callNamedScope($method, $parameters);
         }
 
-        if (in_array($method, $this->passthru)) {
+        if (in_array(strtolower($method), $this->passthru)) {
             return $this->toBase()->{$method}(...$parameters);
         }
 
diff --git a/tests/Database/DatabaseEloquentBuilderTest.php b/tests/Database/DatabaseEloquentBuilderTest.php
index 470214f20a5c..31354f2c1ab0 100755
--- a/tests/Database/DatabaseEloquentBuilderTest.php
+++ b/tests/Database/DatabaseEloquentBuilderTest.php
@@ -2246,6 +2246,48 @@ public function testToRawSql()
         $this->assertSame('select * from "users" where "email" = \'foo\'', $builder->toRawSql());
     }
 
+    public function testPassthruMethodsCallsAreNotCaseSensitive()
+    {
+        $query = m::mock(BaseBuilder::class);
+
+        $mockResponse = 'select 1';
+        $query
+            ->shouldReceive('toRawSql')
+            ->andReturn($mockResponse)
+            ->times(3);
+
+        $builder = new Builder($query);
+
+        $this->assertSame('select 1', $builder->TORAWSQL());
+        $this->assertSame('select 1', $builder->toRawSql());
+        $this->assertSame('select 1', $builder->toRawSQL());
+    }
+
+    public function testPassthruArrayElementsMustAllBeLowercase()
+    {
+        $builder = new class(m::mock(BaseBuilder::class)) extends Builder
+        {
+            // expose protected member for test
+            public function getPassthru(): array
+            {
+                return $this->passthru;
+            }
+        };
+
+        $passthru = $builder->getPassthru();
+
+        foreach ($passthru as $method) {
+            $lowercaseMethod = strtolower($method);
+
+            $this->assertSame(
+                $lowercaseMethod,
+                $method,
+                'Eloquent\\Builder relies on lowercase method names in $passthru array to correctly mimic PHP case-insensitivity on method dispatch.'.
+                    'If you are adding a new method to the $passthru array, make sure the name is lowercased.'
+            );
+        }
+    }
+
     protected function mockConnectionForModel($model, $database)
     {
         $grammarClass = 'Illuminate\Database\Query\Grammars\\'.$database.'Grammar';