diff --git a/assets/pixelpass-256.png b/assets/pixelpass-256.png
new file mode 100644
index 0000000..601c8dc
Binary files /dev/null and b/assets/pixelpass-256.png differ
diff --git a/assets/pixelpass.desktop b/assets/pixelpass.desktop
index 16106a5..73d1964 100644
--- a/assets/pixelpass.desktop
+++ b/assets/pixelpass.desktop
@@ -5,6 +5,7 @@ GenericName=Screen Sharing
 Comment=P2P screen sharing over iroh — no port forwarding, no signup
 Exec=pixelpass --gui
 Icon=pixelpass
+StartupWMClass=pixelpass
 Terminal=false
 Categories=Network;RemoteAccess;
 Keywords=screen;share;sharing;remote;p2p;iroh;cast;
diff --git a/src/gui/mod.rs b/src/gui/mod.rs
index 4d24177..02715b5 100644
--- a/src/gui/mod.rs
+++ b/src/gui/mod.rs
@@ -18,11 +18,25 @@ use self::child::{ChildEvent, ChildProc};
 /// Launch the GUI event loop. Blocks until the window is closed. Runs on the
 /// main thread (a winit requirement), which is where `main` calls it from.
 pub fn run() -> anyhow::Result<()> {
+    // `app_id` must match the installed `pixelpass.desktop`: on Wayland the
+    // compositor sources the titlebar/taskbar icon from that desktop file's
+    // `Icon=` keyed by app_id — not from any pixels the app sets.
+    let mut viewport = egui::ViewportBuilder::default()
+        .with_app_id("pixelpass")
+        .with_inner_size([520.0, 480.0])
+        .with_min_inner_size([460.0, 380.0])
+        .with_title("PixelPass");
+
+    // Pixel icon for X11 titlebars (`_NET_WM_ICON`), embedded at compile time
+    // so the single binary stays self-contained. Non-fatal on failure: Wayland
+    // already has its icon via app_id, and X11 just keeps the generic fallback.
+    match eframe::icon_data::from_png_bytes(include_bytes!("../../assets/pixelpass-256.png")) {
+        Ok(icon) => viewport = viewport.with_icon(icon),
+        Err(e) => tracing::warn!("could not load embedded window icon: {e}"),
+    }
+
     let options = eframe::NativeOptions {
-        viewport: egui::ViewportBuilder::default()
-            .with_inner_size([520.0, 480.0])
-            .with_min_inner_size([460.0, 380.0])
-            .with_title("PixelPass"),
+        viewport,
         ..Default::default()
     };