diff --git a/session/session_test.go b/session/session_test.go
index 8bcea0164eacb..d0fec6758bc53 100644
--- a/session/session_test.go
+++ b/session/session_test.go
@@ -424,6 +424,10 @@ func (s *testSessionSuite) TestGlobalVarAccessor(c *C) {
 	result = tk.MustQuery("select @@autocommit;")
 	result.Check(testkit.Rows("ON"))
 	tk.MustExec("set @@global.autocommit=1")
+
+	_, err = tk.Exec("set global time_zone = 'timezone'")
+	c.Assert(err, NotNil)
+	c.Assert(terror.ErrorEqual(err, variable.ErrUnknownTimeZone), IsTrue)
 }
 
 func (s *testSessionSuite) TestGetSysVariables(c *C) {
diff --git a/sessionctx/variable/varsutil.go b/sessionctx/variable/varsutil.go
index 56bc6dce9bbca..8282334e851a6 100644
--- a/sessionctx/variable/varsutil.go
+++ b/sessionctx/variable/varsutil.go
@@ -301,7 +301,8 @@ func ValidateSetSystemVar(vars *SessionVars, name string, value string) (string,
 		if strings.EqualFold(value, "SYSTEM") {
 			return "SYSTEM", nil
 		}
-		return value, nil
+		_, err := parseTimeZone(value)
+		return value, err
 	case WarningCount, ErrorCount:
 		return value, ErrReadOnly.GenWithStackByArgs(name)
 	case GeneralLog, TiDBGeneralLog, AvoidTemporalUpgrade, BigTables, CheckProxyUsers, CoreFile, EndMakersInJSON, SQLLogBin, OfflineMode,