diff --git a/docker/horizon/extend_start.sh b/docker/horizon/extend_start.sh
index 7ada4c0f2c..d1198adb4b 100644
--- a/docker/horizon/extend_start.sh
+++ b/docker/horizon/extend_start.sh
@@ -193,7 +193,8 @@ function settings_bundle {
     tar -cf- --mtime=1970-01-01 \
         /etc/openstack-dashboard/local_settings \
         /etc/openstack-dashboard/custom_local_settings \
-        /etc/openstack-dashboard/local_settings.d 2> /dev/null || true
+        /etc/openstack-dashboard/local_settings.d \
+        /etc/openstack-dashboard/themes 2> /dev/null || true
 }
 
 function settings_changed {
diff --git a/releasenotes/notes/horizon-theme-rebuilds-65e5f50c1d0cc8dd.yaml b/releasenotes/notes/horizon-theme-rebuilds-65e5f50c1d0cc8dd.yaml
new file mode 100644
index 0000000000..a85f1e5f4f
--- /dev/null
+++ b/releasenotes/notes/horizon-theme-rebuilds-65e5f50c1d0cc8dd.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixed Horizon static asset regeneration for custom theme updates.
+    Changes under ``/etc/openstack-dashboard/themes`` now invalidate the
+    startup settings hash, so Horizon reruns ``collectstatic`` and
+    ``compress`` after a restart or recreate.