diff --git a/modules/programs/fish.nix b/modules/programs/fish.nix
index 73691d5fb..e0ab728eb 100644
--- a/modules/programs/fish.nix
+++ b/modules/programs/fish.nix
@@ -408,7 +408,35 @@ in {
   config = mkIf cfg.enable (mkMerge [
     { home.packages = [ cfg.package ]; }
 
-    (mkIf cfg.generateCompletions {
+    (mkIf cfg.generateCompletions (let
+      generateCompletions = let
+        getName = attrs:
+          attrs.name or "${attrs.pname or "«pname-missing»"}-${
+            attrs.version or "«version-missing»"
+          }";
+      in package:
+      pkgs.runCommand "${getName package}-fish-completions" {
+        srcs = [ package ] ++ filter (p: p != null)
+          (builtins.map (outName: package.${outName} or null)
+            config.home.extraOutputsToInstall);
+        nativeBuildInputs = [ pkgs.python3 ];
+        buildInputs = [ cfg.package ];
+        preferLocalBuild = true;
+      } ''
+        mkdir -p $out
+        for src in $srcs; do
+          if [ -d $src/share/man ]; then
+            find -L $src/share/man -type f \
+              | xargs python ${cfg.package}/share/fish/tools/create_manpage_completions.py --directory $out \
+              > /dev/null
+          fi
+        done
+      '';
+
+      allCompletions =
+        let cmp = (a: b: (a.meta.priority or 0) > (b.meta.priority or 0));
+        in map generateCompletions (sort cmp config.home.packages);
+    in {
       # Support completion for `man` by building a cache for `apropos`.
       programs.man.generateCaches = mkDefault true;
 
@@ -431,36 +459,16 @@ in {
             ${postBuild}
           '';
 
-        generateCompletions = let
-          getName = attrs:
-            attrs.name or "${attrs.pname or "«pname-missing»"}-${
-              attrs.version or "«version-missing»"
-            }";
-        in package:
-        pkgs.runCommand "${getName package}-fish-completions" {
-          srcs = [ package ] ++ filter (p: p != null)
-            (builtins.map (outName: package.${outName} or null)
-              config.home.extraOutputsToInstall);
-          nativeBuildInputs = [ pkgs.python3 ];
-          buildInputs = [ cfg.package ];
-          preferLocalBuild = true;
-        } ''
-          mkdir -p $out
-          for src in $srcs; do
-            if [ -d $src/share/man ]; then
-              find -L $src/share/man -type f \
-                | xargs python ${cfg.package}/share/fish/tools/create_manpage_completions.py --directory $out \
-                > /dev/null
-            fi
-          done
-        '';
       in destructiveSymlinkJoin {
         name = "${config.home.username}-fish-completions";
-        paths =
-          let cmp = (a: b: (a.meta.priority or 0) > (b.meta.priority or 0));
-          in map generateCompletions (sort cmp config.home.packages);
+        paths = allCompletions;
       };
 
+      # For packages with no Fish completions, generateCompletions will build an empty directory,
+      # which means they will not be in our runtime closure. Force a dependency so these do not get
+      # constantly rebuilt.
+      home.extraDependencies = allCompletions;
+
       programs.fish.interactiveShellInit = ''
         # add completions generated by Home Manager to $fish_complete_path
         begin
@@ -472,7 +480,7 @@ in {
           set fish_complete_path $prev "${config.xdg.dataHome}/fish/home-manager_generated_completions" $post
         end
       '';
-    })
+    }))
 
     {
       xdg.configFile."fish/config.fish".source = fishIndent "config.fish" ''