diff --git a/toolkit/components/pictureinpicture/content/player.js b/toolkit/components/pictureinpicture/content/player.js
index 7e084b955598..c56373a24f0f 100644
--- a/toolkit/components/pictureinpicture/content/player.js
+++ b/toolkit/components/pictureinpicture/content/player.js
@@ -342,6 +342,11 @@ let Player = {
             playerBottomControlsDOMRect: this.controlsBottom.getBoundingClientRect(),
           });
         }
+        // The subtitles settings panel gets selected when entering/exiting fullscreen even though
+        // user-select is set to none. I don't know why this happens or how to prevent so we just
+        // remove the selection when fullscreen is entered/exited.
+        let selection = window.getSelection();
+        selection.removeAllRanges();
         break;
       }