diff --git a/humanfriendly/__init__.py b/humanfriendly/__init__.py
index 4c0a333..528ed70 100644
--- a/humanfriendly/__init__.py
+++ b/humanfriendly/__init__.py
@@ -527,7 +527,8 @@ def parse_date(datestring):
     :param datestring: The date/time string to parse.
     :returns: A tuple with the numbers ``(year, month, day, hour, minute,
               second)`` (all numbers are integers).
-    :raises: :exc:`InvalidDate` when the date cannot be parsed.
+    :raises: :exc:`InvalidDate` when the date cannot be parsed or is not a
+             valid calendar date.
 
     Supported date/time formats:
 
@@ -582,10 +583,12 @@ def parse_date(datestring):
         if len(tokens) >= 2:
             date_parts = list(map(int, tokens[0].split('-'))) + [1, 1]
             time_parts = list(map(int, tokens[1].split(':'))) + [0, 0, 0]
-            return tuple(date_parts[0:3] + time_parts[0:3])
+            result = tuple(date_parts[0:3] + time_parts[0:3])
         else:
             year, month, day = (list(map(int, datestring.split('-'))) + [1, 1])[0:3]
-            return (year, month, day, 0, 0, 0)
+            result = (year, month, day, 0, 0, 0)
+        datetime.date(*result[:3])
+        return result
     except Exception:
         msg = "Invalid date! (expected 'YYYY-MM-DD' or 'YYYY-MM-DD HH:MM:SS' but got: %r)"
         raise InvalidDate(format(msg, datestring))
diff --git a/humanfriendly/tests.py b/humanfriendly/tests.py
index 72dad99..564726e 100644
--- a/humanfriendly/tests.py
+++ b/humanfriendly/tests.py
@@ -490,6 +490,25 @@ def test_parse_date(self):
         with self.assertRaises(InvalidDate):
             parse_date('2013-06-XY')
 
+    def test_parse_date_invalid_calendar_dates(self):
+        """Reject impossible dates with and without a time component."""
+        for date in ('2023-02-29', '2024-02-30', '2024-04-31',
+                     '2024-00-10', '2024-13-01', '2024-01-00', '2024-01-32'):
+            for suffix in ('', ' 12:34:56'):
+                with self.assertRaises(InvalidDate):
+                    parse_date(date + suffix)
+
+    def test_parse_date_calendar_boundaries(self):
+        """Keep leap days, month ends, and existing partial-date defaults."""
+        for date, parts in (('2024-02-29', (2024, 2, 29)),
+                            ('2000-02-29', (2000, 2, 29)),
+                            ('2024-04-30', (2024, 4, 30)),
+                            ('2024-12-31', (2024, 12, 31)),
+                            ('2024', (2024, 1, 1)),
+                            ('2024-02', (2024, 2, 1))):
+            self.assertEqual(parse_date(date), parts + (0, 0, 0))
+            self.assertEqual(parse_date(date + ' 12:34:56'), parts + (12, 34, 56))
+
     def test_format_size(self):
         """Test :func:`humanfriendly.format_size()`."""
         self.assertEqual('0 bytes', format_size(0))