diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index e7dd034a8ac..de0180834d2 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -26,7 +26,6 @@ rec {
       broken = stdenv.buildPlatform.is32bit; # since Firefox 60, build on 32-bit platforms fails with "out of memory".
                                              # not in `badPlatforms` because cross-compilation on 64-bit machine might work.
       license = lib.licenses.mpl20;
-      timeout = 28800; # eight hours
     };
     updateScript = callPackage ./update.nix {
       attrPath = "firefox-unwrapped";
diff --git a/pkgs/applications/networking/mailreaders/thunderbird/default.nix b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
index e4debe7a909..57d12b38dcd 100644
--- a/pkgs/applications/networking/mailreaders/thunderbird/default.nix
+++ b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
@@ -332,6 +332,5 @@ stdenv.mkDerivation rec {
     ];
     platforms = platforms.linux;
     license = licenses.mpl20;
-    timeout = 28800; # eight hours
   };
 }