diff --git a/pkgs/desktops/kde-5/plasma/startkde/startkde.sh b/pkgs/desktops/kde-5/plasma/startkde/startkde.sh
index 256f9949e834..d3b460f966b6 100755
--- a/pkgs/desktops/kde-5/plasma/startkde/startkde.sh
+++ b/pkgs/desktops/kde-5/plasma/startkde/startkde.sh
@@ -6,6 +6,34 @@ export QT_PLUGIN_PATH="$QT_PLUGIN_PATH${QT_PLUGIN_PATH:+:}@QT_PLUGIN_PATH@"
 export QML_IMPORT_PATH="$QML_IMPORT_PATH${QML_IMPORT_PATH:+:}@QML_IMPORT_PATH@"
 export QML2_IMPORT_PATH="$QML2_IMPORT_PATH${QML2_IMPORT_PATH:+:}@QML2_IMPORT_PATH@"
 
+# Set the default GTK 2 theme
+if [ ! -e $HOME/.gtkrc-2.0 -a -e /run/current-system/sw/share/themes/Breeze/gtk-2.0/gtkrc ]; then
+    cat >$HOME/.gtkrc-2.0 <<EOF
+# Default GTK+ 2 config for NixOS KDE 5
+include "/run/current-system/sw/share/themes/Breeze/gtk-2.0/gtkrc"
+gtk-theme-name="Breeze"
+gtk-icon-theme-name="breeze"
+gtk-fallback-icon-theme="hicolor"
+gtk-cursor-theme-name="breeze_cursors"
+gtk-toolbar-style=GTK_TOOLBAR_ICONS
+gtk-menu-images=1
+gtk-button-images=1
+EOF
+fi
+
+if [ ! -e $HOME/.config/gtk-3.0/settings.ini -a -e /run/current-system/sw/share/themes/Breeze/gtk-3.0 ]; then
+    cat >$HOME/.config/gtk-3.0/settings.ini <<EOF
+[Settings]
+gtk-theme-name=Breeze
+gtk-icon-theme-name=breeze
+gtk-fallback-icon-theme=hicolor
+gtk-cursor-theme-name=breeze_cursors
+gtk-toolbar-style=GTK_TOOLBAR_ICONS
+gtk-menu-images=1
+gtk-button-images=1
+EOF
+fi
+
 # The KDE icon cache is supposed to update itself
 # automatically, but it uses the timestamp on the icon
 # theme directory as a trigger.  Since in Nix the