diff --git a/src/corelib/time/qdatetimeparser.cpp b/src/corelib/time/qdatetimeparser.cpp
index 64f4e8b7ad5..7d7e120da09 100644
--- a/src/corelib/time/qdatetimeparser.cpp
+++ b/src/corelib/time/qdatetimeparser.cpp
@@ -785,7 +785,7 @@ QDateTimeParser::parseSection(const QDateTime &currentValue, int sectionIndex, i
 
     const int sectionmaxsize = sectionMaxSize(sectionIndex);
     const bool negate = (sn.type == YearSection && m_text.size() > offset
-                         && m_text.at(offset) == u'-');
+                         && calendar.isProleptic() && m_text.at(offset) == u'-');
     const int negativeYearOffset = negate ? 1 : 0;
 
     QStringView sectionTextRef =
@@ -948,6 +948,12 @@ QDateTimeParser::parseSection(const QDateTime &currentValue, int sectionIndex, i
                     } else {
                         result = ParsedSection(Intermediate, lastVal, used);
                     }
+                } else if (!lastVal && !calendar.hasYearZero()
+                           && (sn.type == YearSection
+                               || (sn.type == YearSection2Digits && currentValue.isValid()
+                                   && currentValue.date().year() / 100 == 0))) {
+                    // Year zero prohibited
+                    result = ParsedSection(unfilled ? Acceptable : Invalid, lastVal, used);
                 } else {
                     result = ParsedSection(Acceptable, lastVal, used);
                 }
diff --git a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
index c2c1ce78ba0..66008e29932 100644
--- a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
+++ b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
@@ -3277,6 +3277,8 @@ void tst_QDateTime::fromStringStringFormat_data()
             << u"2001-09-15T09:33:01.001 "_s << u"yyyy-MM-ddThh:mm:ss.z t"_s << 1900 << QDateTime();
     QTest::newRow("invalid-month-year<min") // This used to fail an unfounded assertion.
             << u"0024:91:06 08:52:20"_s << u"yyyy:MM:dd HH:mm:ss"_s << 1900 << QDateTime();
+    QTest::newRow("invalid-year")
+            << u"0000:11:06 08:51:20"_s << u"yyyy:MM:dd HH:mm:ss"_s << 1900 << QDateTime();
 #if QT_CONFIG(timezone)
     QTimeZone southBrazil("America/Sao_Paulo");
     if (southBrazil.isValid()) {