diff --git a/gnu/system.scm b/gnu/system.scm
index 5f562b48b..ce2c05f4e 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -727,7 +727,8 @@ use 'plain-file' instead~%")
   "Return the environment variables of OS for
 @var{session-environment-service-type}, to be used in @file{/etc/environment}."
   `(("LANG" . ,(operating-system-locale os))
-    ("TZ" . ,(operating-system-timezone os))
+    ;; Note: No need to set 'TZ' since (1) we provide /etc/localtime, and (2)
+    ;; it doesn't work for setuid binaries.  See <https://bugs.gnu.org/29212>.
     ("TZDIR" . ,(file-append tzdata "/share/zoneinfo"))
     ;; Tell 'modprobe' & co. where to look for modules.
     ("LINUX_MODULE_DIRECTORY" . "/run/booted-system/kernel/lib/modules")