diff --git a/pkgs/by-name/ni/niri/package.nix b/pkgs/by-name/ni/niri/package.nix
index 3c473ac59cd2..6fd08908d0d7 100644
--- a/pkgs/by-name/ni/niri/package.nix
+++ b/pkgs/by-name/ni/niri/package.nix
@@ -110,6 +110,11 @@ rustPlatform.buildRustPackage (finalAttrs: {
         "-Wl,--pop-state"
       ]
     );
+
+    # Upstream recommends setting the commit hash manually when in a
+    # build environment where the Git repository is unavailable.
+    # See https://github.com/YaLTeR/niri/wiki/Packaging-niri#version-string
+    NIRI_BUILD_COMMIT = "Nixpkgs";
   };
 
   nativeInstallCheckInputs = [ versionCheckHook ];