diff --git a/nixos/modules/programs/tmux.nix b/nixos/modules/programs/tmux.nix
index 2fc1ed63cb36..cadf8d4ae105 100644
--- a/nixos/modules/programs/tmux.nix
+++ b/nixos/modules/programs/tmux.nix
@@ -156,8 +156,13 @@ in {
 
   config = mkIf cfg.enable {
     environment = {
-      systemPackages = [ pkgs.tmux ];
       etc."tmux.conf".text = tmuxConf;
+
+      systemPackages = [ pkgs.tmux ];
+
+      variables = {
+        TMUX_TMPDIR = ''''${XDG_RUNTIME_DIR:-"/run/user/\$(id -u)"}'';
+      };
     };
   };
 }
diff --git a/pkgs/tools/misc/tmux/default.nix b/pkgs/tools/misc/tmux/default.nix
index 4f8a5c05b182..ad15fa98a4b3 100644
--- a/pkgs/tools/misc/tmux/default.nix
+++ b/pkgs/tools/misc/tmux/default.nix
@@ -34,9 +34,6 @@ stdenv.mkDerivation rec {
   postInstall = ''
     mkdir -p $out/share/bash-completion/completions
     cp -v ${bashCompletion}/completions/tmux $out/share/bash-completion/completions/tmux
-
-    wrapProgram $out/bin/tmux \
-      --set TMUX_TMPDIR \''${XDG_RUNTIME_DIR:-"/run/user/\$(id -u)"}
   '';
 
   meta = {