diff --git a/modules/programs/firefox/mkFirefoxModule.nix b/modules/programs/firefox/mkFirefoxModule.nix
index 74639dc7..07df1cf4 100644
--- a/modules/programs/firefox/mkFirefoxModule.nix
+++ b/modules/programs/firefox/mkFirefoxModule.nix
@@ -870,12 +870,12 @@ in
           _: profile:
           let
             chromePath =
-              if ((i: lib.isPath i && lib.pathIsDirectory i) profile.userChrome) then
+              if ((i: (lib.isPath i && lib.pathIsDirectory i) || lib.isDerivation i) profile.userChrome) then
                 "chrome"
               else
                 "chrome/userChrome.css";
             sourcePath =
-              if ((i: lib.isPath i && lib.types.path.check i) profile.userChrome) then
+              if ((i: (lib.isPath i && lib.types.path.check i) || lib.isDerivation i) profile.userChrome) then
                 profile.userChrome
               else
                 null;
diff --git a/tests/modules/programs/firefox/profiles/userchrome/default.nix b/tests/modules/programs/firefox/profiles/userchrome/default.nix
index e016a210..02c68219 100644
--- a/tests/modules/programs/firefox/profiles/userchrome/default.nix
+++ b/tests/modules/programs/firefox/profiles/userchrome/default.nix
@@ -38,6 +38,17 @@ in
           id = 3;
           userChrome = ./chrome;
         };
+        derivation = {
+          id = 4;
+          userChrome = config.lib.test.mkStubPackage {
+            name = "wavefox";
+            buildScript = ''
+              mkdir -p $out
+              ln -s ${./chrome/userChrome.css} $out/userChrome.css
+              echo test > $out/README.md
+            '';
+          };
+        };
       };
     }
     // {
@@ -65,6 +76,12 @@ in
         assertFileContent \
           home-files/${cfg.configPath}/folder/chrome/userChrome.css \
           ${./chrome/userChrome.css}
+
+        assertFileExists \
+          home-files/${cfg.configPath}/derivation/chrome/README.md
+        assertFileContent \
+          home-files/${cfg.configPath}/derivation/chrome/userChrome.css \
+          ${./chrome/userChrome.css}
       '';
     }
   );