diff --git a/Nix.gitignore b/Nix.gitignore
new file mode 100644
index 00000000..298e08cf
--- /dev/null
+++ b/Nix.gitignore
@@ -0,0 +1,5 @@
+# Nix derivation output
+**/result/**
+
+# Nix shell file system overlay (like chroot but per repo)
+.devenv/**