diff --git a/daemon/gdm-wayland-session.c b/daemon/gdm-wayland-session.c
index 3ca2d1496..cb9e96101 100644
--- a/daemon/gdm-wayland-session.c
+++ b/daemon/gdm-wayland-session.c
@@ -287,6 +287,7 @@ spawn_session (State        *state,
                                                     "XAUTHORITY",
                                                     "WAYLAND_DISPLAY",
                                                     "WAYLAND_SOCKET",
+                                                    "__NIXOS_SET_ENVIRONMENT_DONE",
                                                     NULL };
         /* The environment variables listed below are those we have set (or
          * received from our own execution environment) only as a fallback to
diff --git a/daemon/gdm-x-session.c b/daemon/gdm-x-session.c
index ed01fbe52..06efac2df 100644
--- a/daemon/gdm-x-session.c
+++ b/daemon/gdm-x-session.c
@@ -603,6 +603,7 @@ spawn_session (State        *state,
                                                      "XAUTHORITY",
                                                      "WAYLAND_DISPLAY",
                                                      "WAYLAND_SOCKET",
+                                                     "__NIXOS_SET_ENVIRONMENT_DONE",
                                                      NULL };
         /* The environment variables listed below are those we have set (or
          * received from our own execution environment) only as a fallback to