diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+### 3.0.24
+
++ Mark the return value of [applicationGetActiveWindow](https://hackage.haskell.org/package/gi-gtk-3.0.24/docs/GI-Gtk-Objects-Application.html#v:applicationGetActiveWindow) as nullable, see [issue 176](https://github.com/haskell-gi/haskell-gi/issues/176).
+
 ### 3.0.23
 
 + Add an override to make sure that [`Cairo.FontOptions`](https://hackage.haskell.org/package/gi-cairo/docs/GI-Cairo-Structs-FontOptions.html) is always treated as boxed.
diff --git a/Gtk.overrides b/Gtk.overrides
--- a/Gtk.overrides
+++ b/Gtk.overrides
@@ -58,6 +58,10 @@
 # https://gitlab.gnome.org/GNOME/gtk/issues/84
 set-attr Gtk/Widget/drag_dest_find_target/@return-value nullable 1
 
+# Missing nullable return annotation, see
+# https://github.com/haskell-gi/haskell-gi/issues/176
+set-attr Gtk/Application/get_active_window/@return-value nullable 1
+
 if osx
     # Not supported in Quartz version of Gtk
     ignore drag_set_icon_gicon
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Documentation
 Autogenerated documentation for this package can be found at
 
-[https://hackage.haskell.org/package/gi-gtk-3.0.23/docs/GI-Gtk.html](https://hackage.haskell.org/package/gi-gtk-3.0.23/docs/GI-Gtk.html)
+[https://hackage.haskell.org/package/gi-gtk-3.0.24/docs/GI-Gtk.html](https://hackage.haskell.org/package/gi-gtk-3.0.24/docs/GI-Gtk.html)
 
 For general documentation on using [haskell-gi](https://github.com/haskell-gi/haskell-gi) based bindings, see [the project page](https://github.com/haskell-gi/haskell-gi) or [the Wiki](https://github.com/haskell-gi/haskell-gi/wiki).
diff --git a/gi-gtk.cabal b/gi-gtk.cabal
--- a/gi-gtk.cabal
+++ b/gi-gtk.cabal
@@ -1,5 +1,5 @@
 name:                 gi-gtk
-version:              3.0.23
+version:              3.0.24
 synopsis:             Gtk bindings
 description:          Bindings for Gtk, autogenerated by haskell-gi.
 homepage:             https://github.com/haskell-gi/haskell-gi