diff --git a/pkgs/applications/networking/browsers/firefox/packages/firefox-beta.nix b/pkgs/applications/networking/browsers/firefox/packages/firefox-beta.nix
index fc4b697d9388..9f2359782dc9 100644
--- a/pkgs/applications/networking/browsers/firefox/packages/firefox-beta.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages/firefox-beta.nix
@@ -9,11 +9,11 @@
 
 buildMozillaMach rec {
   pname = "firefox-beta";
-  version = "133.0b1";
+  version = "133.0b9";
   applicationName = "Mozilla Firefox Beta";
   src = fetchurl {
     url = "mirror://mozilla/firefox/releases/${version}/source/firefox-${version}.source.tar.xz";
-    sha512 = "c4a85a72b2891c5b6c6e200cd7ef13abe0f5ad090f8ef1d8243a489791f3542b2cd390c141118c4745c4ca677d1e9bf1e564e4a45e066d27ed53e6bd92844727";
+    sha512 = "2c950f04730666387a84b25cfe3afbd93b53988608345a062c8b538619e895c274049fe557a604e86f7ea5744ae2a50dc9c448a20664f0d7308949422a453ae9";
   };
 
   meta = {