diff --git a/pkgs/development/nim-packages/npeg/default.nix b/pkgs/development/nim-packages/npeg/default.nix
index c869ff60f6a5..7969dfb38df3 100644
--- a/pkgs/development/nim-packages/npeg/default.nix
+++ b/pkgs/development/nim-packages/npeg/default.nix
@@ -9,6 +9,7 @@ buildNimPackage rec {
     rev = version;
     hash = "sha256-kN91cp50ZL4INeRWqwrRK6CAkVXUq4rN4YlcN6WL/3Y=";
   };
+  nimFlags = [ "--threads:off" ];
   meta = src.meta // {
     description = "NPeg is a pure Nim pattern matching library";
     maintainers = with lib.maintainers; [ ehmry ];