diff --git a/docs/reference/gdk/gdk4.toml.in b/docs/reference/gdk/gdk4.toml.in
index 0d7d111da7..93f9b4f7f8 100644
--- a/docs/reference/gdk/gdk4.toml.in
+++ b/docs/reference/gdk/gdk4.toml.in
@@ -38,6 +38,7 @@ devhelp = true
 [theme]
 name = "basic"
 show_index_summary = true
+show_class_hierarchy = true
 
 [source-location]
 base_url = "https://gitlab.gnome.org/GNOME/gtk/-/blob/master/"
diff --git a/docs/reference/gsk/gsk4.toml.in b/docs/reference/gsk/gsk4.toml.in
index 047e5498d7..1977bf0a8a 100644
--- a/docs/reference/gsk/gsk4.toml.in
+++ b/docs/reference/gsk/gsk4.toml.in
@@ -33,6 +33,7 @@ devhelp = true
 [theme]
 name = "basic"
 show_index_summary = true
+show_class_hierarchy = true
 
 [source-location]
 base_url = "https://gitlab.gnome.org/GNOME/gtk/-/blob/master/"
diff --git a/docs/reference/gtk/gtk4.toml.in b/docs/reference/gtk/gtk4.toml.in
index 4c5ca3c5e5..4f8737bf6e 100644
--- a/docs/reference/gtk/gtk4.toml.in
+++ b/docs/reference/gtk/gtk4.toml.in
@@ -38,6 +38,7 @@ devhelp = true
 [theme]
 name = "basic"
 show_index_summary = true
+show_class_hierarchy = true
 
 [source-location]
 base_url = "https://gitlab.gnome.org/GNOME/gtk/-/blob/master/"