diff --git a/kcms/fonts/fonts.h b/kcms/fonts/fonts.h
--- a/kcms/fonts/fonts.h
+++ b/kcms/fonts/fonts.h
@@ -184,6 +184,9 @@
 private:
     void updateNeedsSave();
     QFont applyFontDiff(const QFont &fnt, const QFont &newFont, int fontDiffFlags);
+    void saveFontToGtkConfigs();
+    void saveFontToGtk2Config();
+    void saveFontToGtk3Config();
 
     QFont m_defaultFont;
     QFont m_generalFont;
diff --git a/kcms/fonts/fonts.cpp b/kcms/fonts/fonts.cpp
--- a/kcms/fonts/fonts.cpp
+++ b/kcms/fonts/fonts.cpp
@@ -34,6 +34,7 @@
 #include <QFontDialog>
 #include <QApplication>
 #include <QFontDatabase>
+#include <QStandardPaths>
 
 #include <KAcceleratorManager>
 #include <KGlobalSettings>
@@ -568,6 +569,8 @@
     cg = KConfigGroup(config, "WM");
     cg.writeEntry("activeFont", m_windowTitleFont.toString());
     cg.sync();
+    
+    saveFontToGtkConfigs();
 
     m_defaultFontOriginal = m_defaultFont;
     m_generalFontOriginal = m_generalFont;
@@ -602,6 +605,61 @@
     setNeedsSave(false);
 }
 
+void KFonts::saveFontToGtkConfigs() {
+    saveFontToGtk2Config();
+    saveFontToGtk3Config();
+}
+
+void KFonts::saveFontToGtk2Config()
+{
+    QString configPath{QDir::homePath() + "/.gtkrc-2.0"};
+    QFile configFile{configPath};
+
+    if (configFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        QString fileContents{configFile.readAll()};
+
+        QRegularExpression regExp{"gtk-font-name=[^\n]*($|\n)"};
+        
+        QString configValue = QString{
+            m_generalFont.family() + " " +
+            m_generalFont.styleName() + " " +
+            QString::number(m_generalFont.pointSize())
+        };
+        
+        QString newConfigString = QString{"gtk-font-name=\"" + configValue + "\"\n"};
+        
+        if (fileContents.contains(regExp)) {
+            fileContents.replace(regExp, newConfigString);
+        } else {
+            fileContents = QString{newConfigString + "\n"} + fileContents;
+        }
+
+        configFile.remove();
+        configFile.open(QIODevice::WriteOnly | QIODevice::Text);
+        configFile.write(fileContents.toUtf8());
+    } else {
+        qWarning() << "Unable to modify " << configFile.fileName();
+    }
+}
+
+void KFonts::saveFontToGtk3Config()
+{
+    using qsp = QStandardPaths;
+    QString configLocation = qsp::writableLocation(qsp::GenericConfigLocation);
+    QString gtk3ConfigPath{configLocation + "/gtk-3.0/settings.ini"};
+    
+    KSharedConfig::Ptr gtk3Config = KSharedConfig::openConfig(gtk3ConfigPath, KConfig::NoGlobals);
+    KConfigGroup group{gtk3Config, "Settings"};
+    
+    QString configValue = QString{
+        m_generalFont.family() + " " +
+        m_generalFont.styleName() + " " +
+        QString::number(m_generalFont.pointSize())
+    };
+    group.writeEntry("gtk-font-name", configValue);
+    group.sync();
+}
+
 void KFonts::updateNeedsSave()
 {
     setNeedsSave(m_defaultFontOriginal != m_defaultFont ||