diff --git a/glib/gtype.c b/glib/gtype.c
index c9f9527e7..afa327980 100644
--- a/glib/gtype.c
+++ b/glib/gtype.c
@@ -1999,7 +1999,24 @@ g_type_free_instance (GTypeInstance *instance)
 		  NODE_NAME (node));
       return;
     }
-  
+
+  if (G_IS_TYPE_FINALIZABLE (instance))
+    {
+      GTypeFinalizableInterface *iface = G_TYPE_FINALIZABLE_GET_IFACE (instance);
+      GType parent_type = g_type_parent (class->g_type);
+
+      if (iface->finalize != NULL)
+        iface->finalize ((GTypeFinalizable *) instance);
+
+      iface = g_type_interface_peek_parent (iface);
+      while (iface != NULL)
+        {
+          if (iface->finalize != NULL)
+            iface->finalize ((GTypeFinalizable *) instance);
+          iface = g_type_interface_peek_parent (iface);
+        }
+    }
+
   instance->g_class = NULL;
   private_size = node->data->instance.private_size;
   ivar_size = node->data->instance.instance_size;
@@ -4972,3 +4989,10 @@ g_type_init_internal (void)
   _g_value_transforms_init ();
 
 }
+
+static void
+g_type_finalizable_default_init (GTypeFinalizableInterface *iface)
+{
+}
+
+G_DEFINE_INTERFACE (GTypeFinalizable, g_type_finalizable, G_TYPE_INVALID)
diff --git a/glib/gtype.h b/glib/gtype.h
index 0c8d7923c..69f4cb3fc 100644
--- a/glib/gtype.h
+++ b/glib/gtype.h
@@ -427,6 +427,8 @@ typedef struct _GInterfaceInfo          GInterfaceInfo;
 typedef struct _GTypeValueTable         GTypeValueTable;
 typedef struct _GTypeQuery		GTypeQuery;
 
+typedef struct _GTypeFinalizable          GTypeFinalizable;
+typedef struct _GTypeFinalizableInterface GTypeFinalizableInterface;
 
 /* Basic Type Structures
  */
@@ -480,6 +482,34 @@ struct _GTypeQuery
   guint		instance_size;
 };
 
+/**
+ * GTypeFinalizable:
+ *
+ * An interface for finalizable types.
+ *
+ * Instance types that allocate data on the instance structure and wish
+ * to free their resources when [func@GObject.type_free_instance] is called,
+ * should implement the [vfunc@GObject.TypeFinalizable.finalize] virtual
+ * function of this interface.
+ */
+
+/**
+ * GTypeFinalizableInterface:
+ *
+ * An interface for finalizable types.
+ */
+struct _GTypeFinalizableInterface
+{
+  GTypeInterface parent_iface;
+
+  /**
+   * GTypeFinalizableInterface::finalize:
+   * @self: the instance to finalize
+   *
+   * Finalizes the instance data.
+   */
+  void (* finalize) (GTypeFinalizable *self);
+};
 
 /* Casts, checks and accessors for structured types
  * usage of these macros is reserved to type implementations only
@@ -2718,4 +2748,22 @@ const gchar *    g_type_name_from_class         (GTypeClass	*g_class);
  */
 #define GTYPE_TO_POINTER(t) ((gpointer) (guintptr) (t)) GLIB_AVAILABLE_MACRO_IN_2_80
 
+GLIB_AVAILABLE_IN_ALL
+GType g_type_finalizable_get_type (void) G_GNUC_CONST;
+
+G_GNUC_UNUSED static inline GTypeFinalizable *
+G_TYPE_FINALIZABLE (gpointer ptr) {
+  return G_TYPE_CHECK_INSTANCE_CAST (ptr, g_type_finalizable_get_type (), GTypeFinalizable);
+}
+
+G_GNUC_UNUSED static inline gboolean
+G_IS_TYPE_FINALIZABLE (gpointer ptr) {
+  return G_TYPE_CHECK_INSTANCE_TYPE (ptr, g_type_finalizable_get_type ());
+}
+
+G_GNUC_UNUSED static inline GTypeFinalizableInterface *
+G_TYPE_FINALIZABLE_GET_IFACE (gpointer ptr) {
+  return G_TYPE_INSTANCE_GET_INTERFACE (ptr, g_type_finalizable_get_type (), GTypeFinalizableInterface);
+}
+
 G_END_DECLS