diff --git a/pkgs/applications/networking/gmailctl/default.nix b/pkgs/applications/networking/gmailctl/default.nix
index 3e0a20a371c7..8d0b9915d0d7 100644
--- a/pkgs/applications/networking/gmailctl/default.nix
+++ b/pkgs/applications/networking/gmailctl/default.nix
@@ -1,6 +1,7 @@
 { lib
 , buildGoModule
 , fetchFromGitHub
+, installShellFiles
 }:
 
 buildGoModule rec {
@@ -14,6 +15,17 @@ buildGoModule rec {
     sha256 = "sha256-1gOixuOvPHEjnnDNNda9sktnhffovOfeG4XDrLRRMlE=";
   };
 
+  nativeBuildInputs = [
+    installShellFiles
+  ];
+
+  postInstall = ''
+    installShellCompletion --cmd gmailctl \
+      --bash <($out/bin/gmailctl completion bash) \
+      --fish <($out/bin/gmailctl completion fish) \
+      --zsh <($out/bin/gmailctl completion zsh)
+  '';
+
   vendorSha256 = "sha256-Yv3OGHFOmenst/ujUgvCaSEjwwBf3W9n+55ztVhuWjo=";
 
   doCheck = false;