diff --git a/src/gui/text/coretext/qcoretextfontdatabase.mm b/src/gui/text/coretext/qcoretextfontdatabase.mm
index 043272b4c2..88316850e1 100644
--- a/src/gui/text/coretext/qcoretextfontdatabase.mm
+++ b/src/gui/text/coretext/qcoretextfontdatabase.mm
@@ -60,6 +60,8 @@
 #include <QtGui/private/qfontengine_ft_p.h>
 #endif
 
+#include <QtGui/qpa/qwindowsysteminterface.h>
+
 QT_BEGIN_NAMESPACE
 
 // this could become a list of all languages used for each writing
@@ -105,6 +107,12 @@ enum { LanguageCount = sizeof(languageForWritingSystem) / sizeof(const char *) }
 QCoreTextFontDatabase::QCoreTextFontDatabase()
     : m_hasPopulatedAliases(false)
 {
+#if defined(Q_OS_MACOS)
+    m_fontSetObserver = QMacNotificationObserver(nil, NSFontSetChangedNotification, [] {
+        qCDebug(lcQpaFonts) << "Fonts have changed";
+        handleAvailableFontsChanged();
+    });
+#endif
 }
 
 QCoreTextFontDatabase::~QCoreTextFontDatabase()
@@ -223,7 +231,12 @@ void QCoreTextFontDatabase::populateFamily(const QString &familyName)
 
 void QCoreTextFontDatabase::invalidate()
 {
+    qCDebug(lcQpaFonts) << "Invalidating font database";
     m_hasPopulatedAliases = false;
+
+    qDeleteAll(m_themeFonts);
+    m_themeFonts.clear();
+    QWindowSystemInterface::handleThemeChange<QWindowSystemInterface::SynchronousDelivery>(nullptr);
 }
 
 struct FontDescription {
diff --git a/src/gui/text/coretext/qcoretextfontdatabase_p.h b/src/gui/text/coretext/qcoretextfontdatabase_p.h
index b8fa87996d..12f55bd8ad 100644
--- a/src/gui/text/coretext/qcoretextfontdatabase_p.h
+++ b/src/gui/text/coretext/qcoretextfontdatabase_p.h
@@ -97,6 +97,10 @@ private:
     QHash<QString, QList<QCFType<CTFontDescriptorRef>>> m_systemFontDescriptors;
 
     bool m_hasPopulatedAliases;
+
+#if defined(Q_OS_MACOS)
+    QMacNotificationObserver m_fontSetObserver;
+#endif
 };
 
 // Split out into separate template class so that the compiler doesn't have
diff --git a/src/gui/text/qplatformfontdatabase.cpp b/src/gui/text/qplatformfontdatabase.cpp
index 9063075a66..ff678da322 100644
--- a/src/gui/text/qplatformfontdatabase.cpp
+++ b/src/gui/text/qplatformfontdatabase.cpp
@@ -613,6 +613,18 @@ void QPlatformFontDatabase::registerAliasToFontFamily(const QString &familyName,
     qt_registerAliasToFontFamily(familyName, alias);
 }
 
+/*!
+    Inform the Qt font database that the platform's available fonts have changed.
+
+    This will result in invalidating the entire font database.
+
+    \since 6.4
+*/
+void QPlatformFontDatabase::handleAvailableFontsChanged()
+{
+    QFontDatabasePrivate::instance()->invalidate();
+}
+
 /*!
     Helper function that returns true if the font family has already been registered and populated.
 
diff --git a/src/gui/text/qplatformfontdatabase.h b/src/gui/text/qplatformfontdatabase.h
index 74b9e1ba12..0e3d18ffe2 100644
--- a/src/gui/text/qplatformfontdatabase.h
+++ b/src/gui/text/qplatformfontdatabase.h
@@ -139,6 +139,8 @@ public:
     static void registerFontFamily(const QString &familyName);
     static void registerAliasToFontFamily(const QString &familyName, const QString &alias);
 
+    static void handleAvailableFontsChanged();
+
     static bool isFamilyPopulated(const QString &familyName);
 };