diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9f475e59955..b9c428504c9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@
 - Added `displayName` to components using `React.forwardRef` ([#3451](https://github.com/elastic/eui/pull/3451))
 - Added event target checker for `EuiOverlayMask`'s `onClick` prop ([#3462](https://github.com/elastic/eui/pull/3462))
 
+**Bug Fixes**
+
+- Fixed `EuiSuperSelect` not rendering full width when `isOpen` is `true` ([#3495](https://github.com/elastic/eui/pull/3495))
+
 **Deprecations**
 
 - Added a deprecation notice for `EuiNavDrawer` family of components. Advise usage of `EuiCollapsibleNav` instead ([#3487](https://github.com/elastic/eui/pull/3487))
diff --git a/src/components/form/super_select/super_select.tsx b/src/components/form/super_select/super_select.tsx
index 1e3586e74df..6962b8dd465 100644
--- a/src/components/form/super_select/super_select.tsx
+++ b/src/components/form/super_select/super_select.tsx
@@ -110,6 +110,9 @@ export class EuiSuperSelect<T extends string> extends Component<
 
   componentDidMount() {
     this._isMounted = true;
+    if (this.props.isOpen) {
+      this.openPopover();
+    }
   }
 
   componentWillUnmount() {