diff --git a/nixos/modules/programs/zsh/zsh.nix b/nixos/modules/programs/zsh/zsh.nix
index 0c59d20fee46..29790e0dd759 100644
--- a/nixos/modules/programs/zsh/zsh.nix
+++ b/nixos/modules/programs/zsh/zsh.nix
@@ -184,7 +184,7 @@ in
 
         # Tell zsh how to find installed completions.
         for p in ''${(z)NIX_PROFILES}; do
-            fpath+=($p/share/zsh/site-functions $p/share/zsh/$ZSH_VERSION/functions $p/share/zsh/vendor-completions)
+            fpath=($p/share/zsh/site-functions $p/share/zsh/$ZSH_VERSION/functions $p/share/zsh/vendor-completions $fpath)
         done
 
         # Setup custom shell init stuff.