diff --git a/locales/en/translation.json b/locales/en/translation.json
index 434c411eae80c26576d952cdbe2b7d1fe630542d..b5abc9e32a8727044a903968f7d0913146f11279 100644
--- a/locales/en/translation.json
+++ b/locales/en/translation.json
@@ -35,7 +35,9 @@
     "light": "Light",
     "listAllOpenWindows": "List all open windows",
     "manifestError": "The resource cannot be added:",
+    "maximizeWindow": "Maximize window",
     "menu": "Menu",
+    "minimizeWindow": "Minimize window",
     "miradorResources": "Mirador resources",
     "miradorViewer": "Mirador viewer",
     "mosaic": "Mosaic",
diff --git a/src/components/WindowTopBar.js b/src/components/WindowTopBar.js
index f4de6ebc66ca84f85ce24b50e8a6a201c2301750..9b87f235ad8b2e2772fa4320a2a9cdab74cb7300 100644
--- a/src/components/WindowTopBar.js
+++ b/src/components/WindowTopBar.js
@@ -43,7 +43,7 @@ export class WindowTopBar extends Component {
           <WindowTopBarButtons windowId={windowId} />
           <WindowTopMenuButton className={ns('window-menu-btn')} windowId={windowId} />
           <MiradorMenuButton
-            aria-label={t('maximizeWindow')}
+            aria-label={(maximized ? t('minimizeWindow') : t('maximizeWindow'))}
             className={ns('window-maximize')}
             color="inherit"
             onClick={(maximized ? minimizeWindow : maximizeWindow)}