diff --git a/pkgs/development/compilers/zig/0.10.nix b/pkgs/development/compilers/zig/0.10.nix
index 6d41b63f03b2..966be329befc 100644
--- a/pkgs/development/compilers/zig/0.10.nix
+++ b/pkgs/development/compilers/zig/0.10.nix
@@ -47,6 +47,8 @@ stdenv.mkDerivation rec {
   cmakeFlags = [
     # file RPATH_CHANGE could not write new RPATH
     "-DCMAKE_SKIP_BUILD_RPATH=ON"
+
+    # ensure determinism in the compiler build
     "-DZIG_TARGET_MCPU=baseline"
   ];
 
diff --git a/pkgs/development/compilers/zig/0.9.1.nix b/pkgs/development/compilers/zig/0.9.1.nix
index e7c62a4cf938..637186f686e9 100644
--- a/pkgs/development/compilers/zig/0.9.1.nix
+++ b/pkgs/development/compilers/zig/0.9.1.nix
@@ -62,6 +62,9 @@ stdenv.mkDerivation rec {
   cmakeFlags = [
     # file RPATH_CHANGE could not write new RPATH
     "-DCMAKE_SKIP_BUILD_RPATH=ON"
+
+    # ensure determinism in the compiler build
+    "-DZIG_TARGET_MCPU=baseline"
   ];
 
   doCheck = true;