diff --git a/addons/web/static/src/core/overlay/overlay_container.scss b/addons/web/static/src/core/overlay/overlay_container.scss
new file mode 100644
index 00000000000..aff55e9823f
--- /dev/null
+++ b/addons/web/static/src/core/overlay/overlay_container.scss
@@ -0,0 +1,7 @@
+.o-overlay-container > * {
+    // This will make sure that each overlay starts with the same z-index.
+    // The chosen value is over the maximum z-index of the bootstrap components.
+    // See: the zindex-stack in _variables.scss
+    position: relative;
+    z-index: $zindex-tooltip + 1;
+}