diff --git a/pkgs/applications/editors/emacs/elisp-packages/manual-packages.nix b/pkgs/applications/editors/emacs/elisp-packages/manual-packages.nix
index cf33780fa30d..944332e5bc53 100644
--- a/pkgs/applications/editors/emacs/elisp-packages/manual-packages.nix
+++ b/pkgs/applications/editors/emacs/elisp-packages/manual-packages.nix
@@ -81,6 +81,8 @@ in
 
   voicemacs = callPackage ./manual-packages/voicemacs { };
 
+  wat-mode = callPackage ./manual-packages/wat-mode { };
+
   yes-no = callPackage ./manual-packages/yes-no { };
 
   youtube-dl = callPackage ./manual-packages/youtube-dl { };
diff --git a/pkgs/applications/editors/emacs/elisp-packages/manual-packages/wat-mode/default.nix b/pkgs/applications/editors/emacs/elisp-packages/manual-packages/wat-mode/default.nix
new file mode 100644
index 000000000000..8b2e05e4a9ec
--- /dev/null
+++ b/pkgs/applications/editors/emacs/elisp-packages/manual-packages/wat-mode/default.nix
@@ -0,0 +1,23 @@
+# Manually packaged until it is upstreamed to melpa
+# See https://github.com/devonsparks/wat-mode/issues/1
+{ lib, trivialBuild, fetchFromGitHub, fetchpatch, emacs }:
+
+trivialBuild rec {
+  pname = "wat-mode";
+  version = "unstable-2022-07-13";
+
+  src = fetchFromGitHub {
+    owner = "devonsparks";
+    repo = pname;
+    rev = "46b4df83e92c585295d659d049560dbf190fe501";
+    hash = "sha256-jV5V3TRY+D3cPSz3yFwVWn9yInhGOYIaUTPEhsOBxto=";
+  };
+
+  meta = with lib; {
+    homepage = "https://github.com/devonsparks/wat-mode";
+    description = "An Emacs major mode for WebAssembly's text format";
+    license = licenses.gpl3Only;
+    maintainers = with maintainers; [ nagy ];
+    inherit (emacs.meta) platforms;
+  };
+}