diff --git a/docs/reference/gobject/gobject-sections.txt b/docs/reference/gobject/gobject-sections.txt
index 685529708..25ecd3aec 100644
--- a/docs/reference/gobject/gobject-sections.txt
+++ b/docs/reference/gobject/gobject-sections.txt
@@ -17,6 +17,7 @@ G_TYPE_IS_INSTANTIATABLE
 G_TYPE_IS_DERIVABLE
 G_TYPE_IS_DEEP_DERIVABLE
 G_TYPE_IS_INTERFACE
+G_TYPE_IS_FINAL
 GTypeInterface
 GTypeInstance
 GTypeClass
@@ -113,6 +114,9 @@ G_DEFINE_TYPE_WITH_CODE
 G_DEFINE_ABSTRACT_TYPE
 G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE
 G_DEFINE_ABSTRACT_TYPE_WITH_CODE
+G_DEFINE_FINAL_TYPE
+G_DEFINE_FINAL_TYPE_WITH_PRIVATE
+G_DEFINE_FINAL_TYPE_WITH_CODE
 G_ADD_PRIVATE
 G_PRIVATE_OFFSET
 G_PRIVATE_FIELD
diff --git a/gobject/gtype.c b/gobject/gtype.c
index 2cdbe7ce4..422e1cae4 100644
--- a/gobject/gtype.c
+++ b/gobject/gtype.c
@@ -143,7 +143,7 @@
 				    G_TYPE_FLAG_INSTANTIATABLE | \
 				    G_TYPE_FLAG_DERIVABLE | \
 				    G_TYPE_FLAG_DEEP_DERIVABLE)
-#define	TYPE_FLAG_MASK		   (G_TYPE_FLAG_ABSTRACT | G_TYPE_FLAG_VALUE_ABSTRACT)
+#define	TYPE_FLAG_MASK		   (G_TYPE_FLAG_ABSTRACT | G_TYPE_FLAG_VALUE_ABSTRACT | G_TYPE_FLAG_FINAL)
 #define	SIZEOF_FUNDAMENTAL_INFO	   ((gssize) MAX (MAX (sizeof (GTypeFundamentalInfo), \
 						       sizeof (gpointer)), \
                                                   sizeof (glong)))
@@ -804,6 +804,13 @@ check_derivation_I (GType        parent_type,
 		 NODE_NAME (pnode));
       return FALSE;
     }
+  if ((G_TYPE_FLAG_FINAL & GPOINTER_TO_UINT (type_get_qdata_L (pnode, static_quark_type_flags))) == G_TYPE_FLAG_FINAL)
+    {
+      g_warning ("cannot derive '%s' from final parent type '%s'",
+                 type_name,
+                 NODE_NAME (pnode));
+      return FALSE;
+    }
   
   return TRUE;
 }
diff --git a/gobject/gtype.h b/gobject/gtype.h
index f38b4cf4c..f80c4a580 100644
--- a/gobject/gtype.h
+++ b/gobject/gtype.h
@@ -370,6 +370,18 @@ G_BEGIN_DECLS
  * Returns: %TRUE on success
  */
 #define G_TYPE_HAS_VALUE_TABLE(type)            (g_type_value_table_peek (type) != NULL)
+/**
+ * G_TYPE_IS_FINAL:
+ * @type: a #GType value
+ *
+ * Checks if @type is a final type. A final type cannot be derived any
+ * further.
+ *
+ * Returns: %TRUE on success
+ *
+ * Since: 2.70
+ */
+#define G_TYPE_IS_FINAL(type)                   (g_type_test_flags ((type), G_TYPE_FLAG_FINAL)) GLIB_AVAILABLE_MACRO_IN_2_70
 
 
 /* Typedefs
@@ -1002,13 +1014,16 @@ typedef enum    /*< skip >*/
  * @G_TYPE_FLAG_VALUE_ABSTRACT: Indicates an abstract value type, i.e. a type
  *  that introduces a value table, but can't be used for
  *  g_value_init()
+ * @G_TYPE_FLAG_FINAL: Indicates a final type. A final type is a non-derivable
+ *  leaf node in a deep derivable type hierarchy tree. Since: 2.70
  * 
  * Bit masks used to check or determine characteristics of a type.
  */
 typedef enum    /*< skip >*/
 {
-  G_TYPE_FLAG_ABSTRACT		= (1 << 4),
-  G_TYPE_FLAG_VALUE_ABSTRACT	= (1 << 5)
+  G_TYPE_FLAG_ABSTRACT = (1 << 4),
+  G_TYPE_FLAG_VALUE_ABSTRACT = (1 << 5),
+  G_TYPE_FLAG_FINAL GLIB_AVAILABLE_ENUMERATOR_IN_2_70 = (1 << 6)
 } GTypeFlags;
 /**
  * GTypeInfo:
@@ -1685,6 +1700,57 @@ guint     g_type_get_type_registration_serial (void);
  * Since: 2.38
  */
 #define G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE(TN, t_n, T_P)   G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_ABSTRACT, G_ADD_PRIVATE (TN))
+/**
+ * G_DEFINE_FINAL_TYPE:
+ * @TN: the name of the new type, in Camel case
+ * @t_n: the name of the new type, in lower case, with words
+ *   separated by `_` (snake case)
+ * @T_P: the #GType of the parent type
+ *
+ * A convenience macro for type implementations.
+ *
+ * Similar to G_DEFINE_TYPE(), but defines a final type.
+ *
+ * See G_DEFINE_TYPE_EXTENDED() for an example.
+ *
+ * Since: 2.70
+ */
+#define G_DEFINE_FINAL_TYPE(TN, t_n, T_P)                      G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_FINAL, {}) GLIB_AVAILABLE_MACRO_IN_2_70
+/**
+ * G_DEFINE_FINAL_TYPE_WITH_CODE:
+ * @TN: the name of the new type, in Camel case
+ * @t_n: the name of the new type, in lower case, with words
+ *   separated by `_` (snake case)
+ * @T_P: the #GType of the parent type
+ * @_C_: Custom code that gets inserted in the `type_name_get_type()` function.
+ *
+ * A convenience macro for type implementations.
+ *
+ * Similar to G_DEFINE_TYPE_WITH_CODE(), but defines a final type and
+ * allows you to insert custom code into the `*_get_type()` function, e.g.
+ * interface implementations  via G_IMPLEMENT_INTERFACE().
+ *
+ * See G_DEFINE_TYPE_EXTENDED() for an example.
+ *
+ * Since: 2.70
+ */
+#define G_DEFINE_FINAL_TYPE_WITH_CODE(TN, t_n, T_P, _C_)       _G_DEFINE_TYPE_EXTENDED_BEGIN (TN, t_n, T_P, G_TYPE_FLAG_FINAL) {_C_;} _G_DEFINE_TYPE_EXTENDED_END() GLIB_AVAILABLE_MACRO_IN_2_70
+/**
+ * G_DEFINE_FINAL_TYPE_WITH_PRIVATE:
+ * @TN: the name of the new type, in Camel case
+ * @t_n: the name of the new type, in lower case, with words
+ *   separated by `_` (snake case)
+ * @T_P: the #GType of the parent type
+ *
+ * A convenience macro for type implementations.
+ *
+ * Similar to G_DEFINE_TYPE_WITH_PRIVATE(), but defines a final type.
+ *
+ * See G_DEFINE_TYPE_EXTENDED() for an example.
+ *
+ * Since: 2.70
+ */
+#define G_DEFINE_FINAL_TYPE_WITH_PRIVATE(TN, t_n, T_P)         G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_FINAL, G_ADD_PRIVATE (TN)) GLIB_AVAILABLE_MACRO_IN_2_70
 /**
  * G_DEFINE_TYPE_EXTENDED:
  * @TN: The name of the new type, in Camel case.
diff --git a/gobject/tests/meson.build b/gobject/tests/meson.build
index 8837f1a65..e97e1bc7e 100644
--- a/gobject/tests/meson.build
+++ b/gobject/tests/meson.build
@@ -51,6 +51,7 @@ gobject_tests = {
     'source' : ['signals.c', marshalers_h, marshalers_c],
   },
   'testing' : {},
+  'type-flags' : {},
 }
 
 if cc.get_id() != 'msvc'
diff --git a/gobject/tests/type-flags.c b/gobject/tests/type-flags.c
new file mode 100644
index 000000000..249153b55
--- /dev/null
+++ b/gobject/tests/type-flags.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// SPDX-FileCopyrightText: 2021  Emmanuele Bassi
+
+#include <glib-object.h>
+
+#define TEST_TYPE_FINAL (test_final_get_type())
+G_DECLARE_FINAL_TYPE (TestFinal, test_final, TEST, FINAL, GObject)
+
+struct _TestFinal
+{
+  GObject parent_instance;
+};
+
+struct _TestFinalClass
+{
+  GObjectClass parent_class;
+};
+
+G_DEFINE_FINAL_TYPE (TestFinal, test_final, G_TYPE_OBJECT)
+
+static void
+test_final_class_init (TestFinalClass *klass)
+{
+}
+
+static void
+test_final_init (TestFinal *self)
+{
+}
+
+#define TEST_TYPE_FINAL2 (test_final2_get_type())
+G_DECLARE_FINAL_TYPE (TestFinal2, test_final2, TEST, FINAL2, TestFinal)
+
+struct _TestFinal2
+{
+  TestFinal parent_instance;
+};
+
+struct _TestFinal2Class
+{
+  TestFinalClass parent_class;
+};
+
+G_DEFINE_TYPE (TestFinal2, test_final2, TEST_TYPE_FINAL)
+
+static void
+test_final2_class_init (TestFinal2Class *klass)
+{
+}
+
+static void
+test_final2_init (TestFinal2 *self)
+{
+}
+
+/* test_type_flags_final: Check that trying to derive from a final class
+ * will result in a warning from the type system
+ */
+static void
+test_type_flags_final (void)
+{
+  GType final2_type;
+
+  /* This is the message we print out when registering the type */
+  g_test_expect_message ("GLib-GObject", G_LOG_LEVEL_WARNING,
+                         "*cannot derive*");
+
+  /* This is the message when we fail to return from the GOnce init
+   * block within the test_final2_get_type() function
+   */
+  g_test_expect_message ("GLib", G_LOG_LEVEL_CRITICAL,
+                         "*g_once_init_leave: assertion*");
+
+  final2_type = TEST_TYPE_FINAL2;
+  g_assert_true (final2_type == G_TYPE_INVALID);
+
+  g_test_assert_expected_messages ();
+}
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/type/flags/final", test_type_flags_final);
+
+  return g_test_run ();
+}