diff --git a/man3/tzset.3 b/man3/tzset.3
index 05a6898cc..fee6e7304 100644
--- a/man3/tzset.3
+++ b/man3/tzset.3
@@ -60,7 +60,7 @@ found in the system timezone directory (see below).
 .I /etc/localtime
 used here, a symlink to the right file in the system timezone directory.)
 .PP
-If the TZ variable does appear in the environment but its value is NULL
+If the TZ variable does appear in the environment but its value is empty
 or its value cannot be interpreted using any of the formats specified
 below, Coordinated Universal Time (UTC) is used.
 .PP