diff --git a/pkgs/tools/virtualization/nixos-container/nixos-container.pl b/pkgs/tools/virtualization/nixos-container/nixos-container.pl
index 754715cddd0b..677abdb8bc71 100755
--- a/pkgs/tools/virtualization/nixos-container/nixos-container.pl
+++ b/pkgs/tools/virtualization/nixos-container/nixos-container.pl
@@ -14,6 +14,9 @@ my $su = "@su@";
 # Ensure a consistent umask.
 umask 0022;
 
+# Ensure $NIXOS_CONFIG is not set.
+$ENV{"NIXOS_CONFIG"} = "";
+
 # Parse the command line.
 
 sub showHelp {