diff --git a/decorations/settings.h b/decorations/settings.h
--- a/decorations/settings.h
+++ b/decorations/settings.h
@@ -49,6 +49,9 @@
     QVector< KDecoration2::DecorationButtonType > decorationButtonsRight() const override {
         return m_rightButtons;
     }
+    QFont font() const override {
+        return m_font;
+    }
 
 private:
     void readSettings();
@@ -59,6 +62,7 @@
     QVector< KDecoration2::DecorationButtonType > m_rightButtons;
     KDecoration2::BorderSize m_borderSize;
     bool m_closeDoubleClickMenu = false;
+    QFont m_font;
 };
 } // Decoration
 } // KWin
diff --git a/decorations/settings.cpp b/decorations/settings.cpp
--- a/decorations/settings.cpp
+++ b/decorations/settings.cpp
@@ -30,6 +30,8 @@
 
 #include <KConfigGroup>
 
+#include <QFontDatabase>
+
 namespace KWin
 {
 namespace Decoration
@@ -183,6 +185,11 @@
         m_borderSize = size;
         emit decorationSettings()->borderSizeChanged(m_borderSize);
     }
+    const QFont font = QFontDatabase::systemFont(QFontDatabase::TitleFont);
+    if (font != m_font) {
+        m_font = font;
+        emit decorationSettings()->fontChanged(m_font);
+    }
 
     emit decorationSettings()->reconfigured();
 }