diff --git a/pkgs/by-name/wo/wormhole-william/package.nix b/pkgs/by-name/wo/wormhole-william/package.nix
index aeecc73e64d9..eaf637ea3843 100644
--- a/pkgs/by-name/wo/wormhole-william/package.nix
+++ b/pkgs/by-name/wo/wormhole-william/package.nix
@@ -1,4 +1,4 @@
-{ lib, buildGoModule, fetchFromGitHub }:
+{ lib, stdenv, buildGoModule, fetchFromGitHub, installShellFiles }:
 
 buildGoModule rec {
   pname = "wormhole-william";
@@ -22,6 +22,15 @@ buildGoModule rec {
                 "SkipWormholeDirectoryTransportSendRecvDirect"
   '';
 
+  nativeBuildInputs = [ installShellFiles ];
+
+  postInstall = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
+    installShellCompletion --cmd wormhole-william \
+      --bash <($out/bin/wormhole-william shell-completion bash) \
+      --fish <($out/bin/wormhole-william shell-completion fish) \
+      --zsh <($out/bin/wormhole-william shell-completion zsh)
+  '';
+
   meta = with lib; {
     homepage = "https://github.com/psanford/wormhole-william";
     description = "End-to-end encrypted file transfers";