diff --git a/glib/gdatetime.c b/glib/gdatetime.c
index 3be4eba3d..f8bf31c43 100644
--- a/glib/gdatetime.c
+++ b/glib/gdatetime.c
@@ -1194,6 +1194,11 @@ get_iso8601_seconds (const gchar *text, gsize length, gdouble *value)
 
   if (length > 2 && !(text[i] == '.' || text[i] == ','))
     return FALSE;
+
+  /* Ignore leap seconds, see g_date_time_new_from_iso8601() */
+  if (v >= 60.0 && v <= 61.0)
+    v = 59.0;
+
   i++;
   if (i == length)
     return FALSE;
@@ -1431,6 +1436,10 @@ parse_iso8601_time (const gchar *text, gsize length,
  * [ISO 8601 formatted string](https://en.wikipedia.org/wiki/ISO_8601)
  * @text. ISO 8601 strings of the form <date><sep><time><tz> are supported.
  *
+ * Note that as #GDateTime "is oblivious to leap seconds", leap seconds information
+ * in an ISO-8601 string will be ignored, so a `23:59:60` time would be parsed as
+ * `23:59:59`.
+ *
  * <sep> is the separator and can be either 'T', 't' or ' '.
  *
  * <date> is in the form:
diff --git a/glib/tests/gdatetime.c b/glib/tests/gdatetime.c
index 4ecccb347..7b95f626b 100644
--- a/glib/tests/gdatetime.c
+++ b/glib/tests/gdatetime.c
@@ -818,6 +818,7 @@ test_GDateTime_new_from_iso8601_2 (void)
     { TRUE, "1970-01-01T00:00:17.1234Z", 1970, 1, 1, 0, 0, 17, 123400, 0 },
     { TRUE, "1970-01-01T00:00:17.123456Z", 1970, 1, 1, 0, 0, 17, 123456, 0 },
     { TRUE, "1980-02-22T12:36:00+02:00", 1980, 2, 22, 12, 36, 0, 0, 2 * G_TIME_SPAN_HOUR },
+    { TRUE, "1990-12-31T15:59:60-08:00", 1990, 12, 31, 15, 59, 59, 0, -8 * G_TIME_SPAN_HOUR },
     { FALSE, "   ", 0, 0, 0, 0, 0, 0, 0, 0 },
     { FALSE, "x", 0, 0, 0, 0, 0, 0, 0, 0 },
     { FALSE, "123x", 0, 0, 0, 0, 0, 0, 0, 0 },