diff --git a/src/ui.rs b/src/ui.rs
index 2a43a75..f22e1da 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -216,6 +216,7 @@ impl Ui {
     pub fn build(app: &Application) -> Rc<RefCell<Ui>> {
         debug!("building ui");
         let open_file_button = Button::from_icon_name("document-open");
+        let fullscreen_button = Button::from_icon_name("view-fullscreen");
         let normal_color_mode_button = ToggleButton::builder().label("Std").active(true).build();
         let dark_color_mode_button = ToggleButton::builder()
             .label("Dark")
@@ -227,7 +228,7 @@ impl Ui {
             .build();
 
         let button_container = Box::builder()
-            .spacing(5)
+            .spacing(10)
             .hexpand(true)
             .orientation(gtk::Orientation::Horizontal)
             .build();
@@ -240,6 +241,7 @@ impl Ui {
         color_mode_button_container.append(&dark_color_mode_button);
         color_mode_button_container.append(&sepia_color_mode_button);
         button_container.append(&open_file_button);
+        button_container.append(&fullscreen_button);
         button_container.append(&color_mode_button_container);
 
         let image_container = Box::builder()
@@ -327,6 +329,11 @@ impl Ui {
                 choose_file(Rc::clone(&ui), &ui.borrow().window);
             }),
         );
+        fullscreen_button.connect_clicked(
+            glib::clone!(@strong ui => @default-panic, move |_button| {
+                toggle_fullscreen(&ui.borrow());
+            }),
+        );
         normal_color_mode_button.connect_clicked(
             glib::clone!(@strong ui => @default-panic, move |_button| {
             switch_color_mode(Rc::clone(&ui), ColorMode::Normal);