diff --git a/src/wp-includes/post-functions.php b/src/wp-includes/post-functions.php
index 05663968de..1c410d7674 100644
--- a/src/wp-includes/post-functions.php
+++ b/src/wp-includes/post-functions.php
@@ -835,10 +835,11 @@ function get_post_type( $post = null ) {
 function get_post_type_object( $post_type ) {
 	global $wp_post_types;
 
-	if ( empty($wp_post_types[$post_type]) )
+	if ( ! is_scalar( $post_type ) || empty( $wp_post_types[ $post_type ] ) ) {
 		return null;
+	}
 
-	return $wp_post_types[$post_type];
+	return $wp_post_types[ $post_type ];
 }
 
 /**
diff --git a/tests/phpunit/tests/post/types.php b/tests/phpunit/tests/post/types.php
index e1ead02003..5a1be694d8 100644
--- a/tests/phpunit/tests/post/types.php
+++ b/tests/phpunit/tests/post/types.php
@@ -122,4 +122,24 @@ class Tests_Post_Types extends WP_UnitTestCase {
 		return $labels;
 	}
 
+
+	/**
+	 * @ticket 30013
+	 */
+	public function test_get_post_type_object_with_non_scalar_values() {
+		$this->assertFalse( post_type_exists( 'foo' ) );
+
+		register_post_type( 'foo' );
+
+		$this->assertTrue( post_type_exists( 'foo' ) );
+
+		$this->assertNotNull( get_post_type_object( 'foo' ) );
+		$this->assertNull( get_post_type_object( array() ) );
+		$this->assertNull( get_post_type_object( array( 'foo' ) ) );
+		$this->assertNull( get_post_type_object( new stdClass ) );
+
+		_unregister_post_type( 'foo' );
+
+		$this->assertFalse( post_type_exists( 'foo' ) );
+	}
 }