diff --git a/pgtype/timestamp.go b/pgtype/timestamp.go
index 677a2c6e..ff2739d6 100644
--- a/pgtype/timestamp.go
+++ b/pgtype/timestamp.go
@@ -104,8 +104,8 @@ func (ts *Timestamp) UnmarshalJSON(b []byte) error {
 	case "-infinity":
 		*ts = Timestamp{Valid: true, InfinityModifier: -Infinity}
 	default:
-		// PostgreSQL uses ISO 8601 for to_json function and casting from a string to timestamptz
-		tim, err := time.Parse(time.RFC3339Nano, *s)
+		// PostgreSQL uses ISO 8601 wihout timezone for to_json function and casting from a string to timestampt
+		tim, err := time.Parse(time.RFC3339Nano, *s+"Z")
 		if err != nil {
 			return err
 		}
@@ -225,7 +225,6 @@ func discardTimeZone(t time.Time) time.Time {
 }
 
 func (c *TimestampCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
-
 	switch format {
 	case BinaryFormatCode:
 		switch target.(type) {
diff --git a/pgtype/timestamp_test.go b/pgtype/timestamp_test.go
index 31b3ad82..345da819 100644
--- a/pgtype/timestamp_test.go
+++ b/pgtype/timestamp_test.go
@@ -128,8 +128,8 @@ func TestTimestampUnmarshalJSON(t *testing.T) {
 		result pgtype.Timestamp
 	}{
 		{source: "null", result: pgtype.Timestamp{}},
-		{source: "\"2012-03-29T10:05:45Z\"", result: pgtype.Timestamp{Time: time.Date(2012, 3, 29, 10, 5, 45, 0, time.UTC), Valid: true}},
-		{source: "\"2012-03-29T10:05:45.555Z\"", result: pgtype.Timestamp{Time: time.Date(2012, 3, 29, 10, 5, 45, 555*1000*1000, time.UTC), Valid: true}},
+		{source: "\"2012-03-29T10:05:45\"", result: pgtype.Timestamp{Time: time.Date(2012, 3, 29, 10, 5, 45, 0, time.UTC), Valid: true}},
+		{source: "\"2012-03-29T10:05:45.555\"", result: pgtype.Timestamp{Time: time.Date(2012, 3, 29, 10, 5, 45, 555*1000*1000, time.UTC), Valid: true}},
 		{source: "\"infinity\"", result: pgtype.Timestamp{InfinityModifier: pgtype.Infinity, Valid: true}},
 		{source: "\"-infinity\"", result: pgtype.Timestamp{InfinityModifier: pgtype.NegativeInfinity, Valid: true}},
 	}