diff --git a/src/font-stylesheet-timeout.js b/src/font-stylesheet-timeout.js
index fc74d9a0e3e9..c7a568a4f67a 100644
--- a/src/font-stylesheet-timeout.js
+++ b/src/font-stylesheet-timeout.js
@@ -123,7 +123,7 @@ function timeoutFontFaces(win) {
   }
   const doc = win.document;
   // TODO(@cramforce) Switch to .values when FontFaceSet extern supports it.
-  if (!doc.fonts && !doc.fonts['values']) {
+  if (!doc.fonts || !doc.fonts['values']) {
     return;
   }
   const it = doc.fonts['values']();