diff --git a/src/corelib/text/qstringconverter.cpp b/src/corelib/text/qstringconverter.cpp
index 329e1990da..a0e0173cbb 100644
--- a/src/corelib/text/qstringconverter.cpp
+++ b/src/corelib/text/qstringconverter.cpp
@@ -571,6 +571,21 @@ char *QUtf8::convertFromUnicode(char *out, QStringView in, QStringConverter::Sta
     return reinterpret_cast<char *>(cursor);
 }
 
+char *QUtf8::convertFromLatin1(char *out, QLatin1StringView in)
+{
+    // ### SIMD-optimize:
+    for (uchar ch : in) {
+        if (ch < 128) {
+            *out++ = ch;
+        } else {
+            // as per https://en.wikipedia.org/wiki/UTF-8#Encoding, 2nd row
+            *out++ = 0b110'0'0000u | (ch >> 6);
+            *out++ = 0b10'00'0000u | (ch & 0b0011'1111);
+        }
+    }
+    return out;
+}
+
 QString QUtf8::convertToUnicode(QByteArrayView in)
 {
     // UTF-8 to UTF-16 always needs the exact same number of words or less:
diff --git a/src/corelib/text/qstringconverter_p.h b/src/corelib/text/qstringconverter_p.h
index e801272646..26be8b713c 100644
--- a/src/corelib/text/qstringconverter_p.h
+++ b/src/corelib/text/qstringconverter_p.h
@@ -270,6 +270,7 @@ struct QUtf8
     Q_CORE_EXPORT static QByteArray convertFromUnicode(QStringView in);
     Q_CORE_EXPORT static QByteArray convertFromUnicode(QStringView in, QStringConverterBase::State *state);
     static char *convertFromUnicode(char *out, QStringView in, QStringConverter::State *state);
+    Q_CORE_EXPORT static char *convertFromLatin1(char *out, QLatin1StringView in);
     struct ValidUtf8Result {
         bool isValidUtf8;
         bool isValidAscii;
diff --git a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
index a346615e39..a60478d542 100644
--- a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
+++ b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
@@ -6,9 +6,11 @@
 
 #include <QtCore/private/qglobal_p.h>
 #include <qstringconverter.h>
+#include <private/qstringconverter_p.h>
 #include <qthreadpool.h>
 
 #include <array>
+#include <numeric>
 
 using namespace Qt::StringLiterals;
 
@@ -130,6 +132,8 @@ private slots:
     void roundtrip_data();
     void roundtrip();
 
+    void convertL1U8();
+
 #if QT_CONFIG(icu)
     void roundtripIcu_data();
     void roundtripIcu();
@@ -427,6 +431,18 @@ void tst_QStringConverter::roundtrip()
     QCOMPARE(decoded, uniString);
 }
 
+void tst_QStringConverter::convertL1U8()
+{
+    {
+        std::array<char, 256> latin1;
+        std::iota(latin1.data(), latin1.data() + latin1.size(), uchar(0));
+        std::array<char, 512> utf8;
+        auto out = QUtf8::convertFromLatin1(utf8.data(), QLatin1StringView{latin1.data(), latin1.size()});
+        QCOMPARE(QString::fromLatin1(latin1.data(), latin1.size()),
+                 QString::fromUtf8(utf8.data(), out - utf8.data()));
+    }
+}
+
 #if QT_CONFIG(icu)
 
 void tst_QStringConverter::roundtripIcu_data()