diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index 01e75b662..fc8115c31 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -626,6 +626,9 @@ static void dispatch_message_real(
                         }
 
                         free(c);
+                } else if (unit_id) {
+                        x = strappenda("_SYSTEMD_UNIT=", unit_id);
+                        IOVEC_SET_STRING(iovec[n++], x);
                 }
 
 #ifdef HAVE_SELINUX