diff --git a/harness/temporalHelpers.js b/harness/temporalHelpers.js
index 657a580f37..8a9e5b9773 100644
--- a/harness/temporalHelpers.js
+++ b/harness/temporalHelpers.js
@@ -369,7 +369,7 @@ var TemporalHelpers = {
     assert(expected instanceof Temporal.ZonedDateTime, `${prefix}expected value should be a Temporal.ZonedDateTime`);
     assert(actual instanceof Temporal.ZonedDateTime, `${prefix}instanceof`);
     assert(actual.equals(expected), `${prefix}equals method`);
-    assert.sameValue(actual.timeZone, expected.timeZone, `${prefix}time zone same value:`);
+    assert.sameValue(actual.timeZoneId, expected.timeZoneId, `${prefix}time zone same value:`);
     assert.sameValue(
       actual.calendarId,
       expected.calendarId,
diff --git a/test/built-ins/Temporal/ZonedDateTime/from/argument-zoneddatetime.js b/test/built-ins/Temporal/ZonedDateTime/from/argument-zoneddatetime.js
index 99bbc6c99f..207aac6fe1 100644
--- a/test/built-ins/Temporal/ZonedDateTime/from/argument-zoneddatetime.js
+++ b/test/built-ins/Temporal/ZonedDateTime/from/argument-zoneddatetime.js
@@ -11,7 +11,7 @@ const orig = new Temporal.ZonedDateTime(946684800_000_000_010n, "UTC");
 const result = Temporal.ZonedDateTime.from(orig);
 
 assert.sameValue(result.epochNanoseconds, 946684800_000_000_010n, "ZonedDateTime is copied");
-assert.sameValue(result.timeZone, orig.timeZone, "time zone is the same");
+assert.sameValue(result.timeZoneId, orig.timeZoneId, "time zone is the same");
 assert.sameValue(result.calendarId, orig.calendarId, "calendar is the same");
 
 assert.notSameValue(