diff --git a/src/Type/Definition/Config.php b/src/Type/Definition/Config.php
index 024a9e5..07616a5 100644
--- a/src/Type/Definition/Config.php
+++ b/src/Type/Definition/Config.php
@@ -26,6 +26,7 @@ class Config
     const REQUIRED = 65536;
     const KEY_AS_NAME = 131072;
     const MAYBE_THUNK = 262144;
+    const MAYBE_TYPE = 524288;
 
     /**
      * @var bool
@@ -155,7 +156,11 @@ class Config
 
                 foreach ($value as $arrKey => $arrValue) {
                     if (is_array($def->definition)) {
-                        Utils::invariant(is_array($arrValue), $err, $arrKey, Utils::getVariableType($arrValue));
+                        if ($def->flags & self::MAYBE_TYPE) {
+                            Utils::invariant(is_array($arrValue) || $arrValue instanceof Type, $err, $arrKey, Utils::getVariableType($arrValue));
+                        } else {
+                            Utils::invariant(is_array($arrValue), $err, $arrKey, Utils::getVariableType($arrValue));
+                        }
 
                         if ($def->flags & self::KEY_AS_NAME) {
                             $arrValue += ['name' => $arrKey];
diff --git a/src/Type/Definition/ObjectType.php b/src/Type/Definition/ObjectType.php
index 7d84199..6836e89 100644
--- a/src/Type/Definition/ObjectType.php
+++ b/src/Type/Definition/ObjectType.php
@@ -86,7 +86,7 @@ class ObjectType extends Type implements OutputType, CompositeType
             'name' => Config::STRING | Config::REQUIRED,
             'fields' => Config::arrayOf(
                 FieldDefinition::getDefinition(),
-                Config::KEY_AS_NAME | Config::MAYBE_THUNK
+                Config::KEY_AS_NAME | Config::MAYBE_THUNK | Config::MAYBE_TYPE
             ),
             'description' => Config::STRING,
             'interfaces' => Config::arrayOf(
diff --git a/tests/Executor/ExecutorTest.php b/tests/Executor/ExecutorTest.php
index 85a7339..bcd6720 100644
--- a/tests/Executor/ExecutorTest.php
+++ b/tests/Executor/ExecutorTest.php
@@ -404,7 +404,7 @@ class ExecutorTest extends \PHPUnit_Framework_TestCase
 
         $result = Executor::execute($schema, $docAst, $data);
 
-        $this->assertEquals($expected, $result->toArray());
+        $this->assertArraySubset($expected, $result->toArray());
     }
 
     /**
diff --git a/tests/Executor/ListsTest.php b/tests/Executor/ListsTest.php
index 1588034..6ec9a59 100644
--- a/tests/Executor/ListsTest.php
+++ b/tests/Executor/ListsTest.php
@@ -41,7 +41,7 @@ class ListsTest extends \PHPUnit_Framework_TestCase
         $ast = Parser::parse('{ nest { test } }');
 
         $result = Executor::execute($schema, $ast, $data);
-        $this->assertEquals($expected, $result->toArray());
+        $this->assertArraySubset($expected, $result->toArray());
     }
 
     // Describe: Execute: Handles list nullability
diff --git a/tests/Executor/MutationsTest.php b/tests/Executor/MutationsTest.php
index 5f04302..07f67be 100644
--- a/tests/Executor/MutationsTest.php
+++ b/tests/Executor/MutationsTest.php
@@ -114,7 +114,7 @@ class MutationsTest extends \PHPUnit_Framework_TestCase
                 )
             ]
         ];
-        $this->assertEquals($expected, $mutationResult->toArray());
+        $this->assertArraySubset($expected, $mutationResult->toArray());
     }
 
     private function schema()
diff --git a/tests/Executor/NonNullTest.php b/tests/Executor/NonNullTest.php
index c0b67ef..74f4604 100644
--- a/tests/Executor/NonNullTest.php
+++ b/tests/Executor/NonNullTest.php
@@ -99,7 +99,7 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 )
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
     }
 
     public function testNullsASynchronouslyReturnedObjectThatContainsANonNullableFieldThatThrowsSynchronously()
@@ -123,7 +123,7 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 FormattedError::create($this->nonNullSyncError->getMessage(), [new SourceLocation(4, 11)])
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
     }
 
     public function testNullsAComplexTreeOfNullableFieldsThatThrow()
@@ -155,7 +155,7 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 FormattedError::create($this->syncError->getMessage(), [new SourceLocation(6, 13)]),
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, $ast, $this->throwingData, null, [], 'Q')->toArray());
     }
 
     public function testNullsANullableFieldThatSynchronouslyReturnsNull()
@@ -197,7 +197,7 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 FormattedError::create('Cannot return null for non-nullable field DataType.nonNullSync.', [new SourceLocation(4, 11)])
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, $ast, $this->nullingData, null, [], 'Q')->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, $ast, $this->nullingData, null, [], 'Q')->toArray());
     }
 
     public function test5()
@@ -247,7 +247,7 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 FormattedError::create($this->nonNullSyncError->getMessage(), [new SourceLocation(2, 17)])
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, Parser::parse($doc), $this->throwingData)->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, Parser::parse($doc), $this->throwingData)->toArray());
     }
 
     public function testNullsTheTopLevelIfSyncNonNullableFieldReturnsNull()
@@ -262,6 +262,6 @@ class NonNullTest extends \PHPUnit_Framework_TestCase
                 FormattedError::create('Cannot return null for non-nullable field DataType.nonNullSync.', [new SourceLocation(2, 17)]),
             ]
         ];
-        $this->assertEquals($expected, Executor::execute($this->schema, Parser::parse($doc), $this->nullingData)->toArray());
+        $this->assertArraySubset($expected, Executor::execute($this->schema, Parser::parse($doc), $this->nullingData)->toArray());
     }
 }
diff --git a/tests/Type/EnumTypeTest.php b/tests/Type/EnumTypeTest.php
index e15a4ee..ef32c1c 100644
--- a/tests/Type/EnumTypeTest.php
+++ b/tests/Type/EnumTypeTest.php
@@ -423,7 +423,7 @@ class EnumTypeTest extends \PHPUnit_Framework_TestCase
             ]]
         ];
 
-        $this->assertEquals($expected, $result);
+        $this->assertArraySubset($expected, $result);
     }
 
     /**
@@ -443,7 +443,7 @@ class EnumTypeTest extends \PHPUnit_Framework_TestCase
             third: simpleEnum(fromValue: "WRONG")
         }';
 
-        $this->assertEquals(
+        $this->assertArraySubset(
             [
                 'data' => ['first' => 'ONE', 'second' => 'TWO', 'third' => null],
                 'errors' => [[