diff --git a/src/apprt/gtk-ng/build/gresource.zig b/src/apprt/gtk-ng/build/gresource.zig
index 103e8a063..dd9bf7de9 100644
--- a/src/apprt/gtk-ng/build/gresource.zig
+++ b/src/apprt/gtk-ng/build/gresource.zig
@@ -30,6 +30,7 @@ pub const icon_sizes: []const comptime_int = &.{ 16, 32, 128, 256, 512, 1024 };
 ///
 /// These will be asserted to exist at runtime.
 pub const blueprints: []const Blueprint = &.{
+    .{ .major = 1, .minor = 2, .name = "close-confirmation-dialog" },
     .{ .major = 1, .minor = 2, .name = "config-errors-dialog" },
     .{ .major = 1, .minor = 2, .name = "surface" },
     .{ .major = 1, .minor = 5, .name = "window" },
diff --git a/src/apprt/gtk-ng/class/application.zig b/src/apprt/gtk-ng/class/application.zig
index 8865fd137..22a27c57d 100644
--- a/src/apprt/gtk-ng/class/application.zig
+++ b/src/apprt/gtk-ng/class/application.zig
@@ -28,6 +28,7 @@ const Common = @import("../class.zig").Common;
 const WeakRef = @import("../weak_ref.zig").WeakRef;
 const Config = @import("config.zig").Config;
 const Window = @import("window.zig").Window;
+const CloseConfirmationDialog = @import("close_confirmation_dialog.zig").CloseConfirmationDialog;
 const ConfigErrorsDialog = @import("config_errors_dialog.zig").ConfigErrorsDialog;
 
 const log = std.log.scoped(.gtk_ghostty_application);
@@ -110,6 +111,15 @@ pub const Application = extern struct {
         /// only be set by the main loop thread.
         running: bool = false,
 
+        /// The timer used to quit the application after the last window is
+        /// closed. Even if there is no quit delay set, this is the state
+        /// used to determine to close the app.
+        quit_timer: union(enum) {
+            off,
+            active: c_uint,
+            expired,
+        } = .off,
+
         /// If non-null, we're currently showing a config errors dialog.
         /// This is a WeakRef because the dialog can close on its own
         /// outside of our own lifecycle and that's okay.
@@ -309,6 +319,9 @@ pub const Application = extern struct {
 
         // The final cleanup that is always required at the end of running.
         defer {
+            // Ensure our timer source is removed
+            self.stopQuitTimer();
+
             // Sync any remaining settings
             gio.Settings.sync();
 
@@ -378,19 +391,64 @@ pub const Application = extern struct {
                 if (!config.@"quit-after-last-window-closed") break :q false;
 
                 // If the quit timer has expired, quit.
-                // if (self.quit_timer == .expired) break :q true;
+                if (priv.quit_timer == .expired) break :q true;
 
                 // There's no quit timer running, or it hasn't expired, don't quit.
                 break :q false;
             };
 
-            if (must_quit) {
-                //self.quit();
-                priv.running = false;
-            }
+            if (must_quit) self.quit();
         }
     }
 
+    /// Quit the application. This will start the process to stop the
+    /// run loop. It will not `posix.exit`.
+    pub fn quit(self: *Self) void {
+        const priv = self.private();
+
+        // If our run loop has already exited then we are done.
+        if (!priv.running) return;
+
+        // If our core app doesn't need to confirm quit then we
+        // can exit immediately.
+        if (!priv.core_app.needsConfirmQuit()) {
+            self.quitNow();
+            return;
+        }
+
+        // Show a confirmation dialog
+        const dialog: *CloseConfirmationDialog = .new(.app);
+
+        // Connect to the reload signal so we know to reload our config.
+        _ = CloseConfirmationDialog.signals.@"close-request".connect(
+            dialog,
+            *Application,
+            handleCloseConfirmation,
+            self,
+            .{},
+        );
+
+        // Show it
+        dialog.present();
+    }
+
+    fn quitNow(self: *Self) void {
+        // Get all our windows and destroy them, forcing them to
+        // free their memory.
+        const list = gtk.Window.listToplevels();
+        defer list.free();
+        list.foreach(struct {
+            fn callback(data: ?*anyopaque, _: ?*anyopaque) callconv(.c) void {
+                const ptr = data orelse return;
+                const window: *gtk.Window = @ptrCast(@alignCast(ptr));
+                window.destroy();
+            }
+        }.callback, null);
+
+        // Trigger our runloop exit.
+        self.private().running = false;
+    }
+
     /// apprt API to perform an action.
     pub fn performAction(
         self: *Self,
@@ -418,6 +476,8 @@ pub const Application = extern struct {
 
             .pwd => Action.pwd(target, value),
 
+            .quit => self.quit(),
+
             .quit_timer => try Action.quitTimer(self, value),
 
             .render => Action.render(self, target),
@@ -425,7 +485,6 @@ pub const Application = extern struct {
             .set_title => Action.setTitle(target, value),
 
             // Unimplemented but todo on gtk-ng branch
-            .quit,
             .close_window,
             .toggle_maximize,
             .toggle_fullscreen,
@@ -525,6 +584,51 @@ pub const Application = extern struct {
         return &self.private().winproto;
     }
 
+    /// This will get called when there are no more open surfaces.
+    fn startQuitTimer(self: *Self) void {
+        const priv = self.private();
+        const config = priv.config.get();
+
+        // Cancel any previous timer.
+        self.stopQuitTimer();
+
+        // This is a no-op unless we are configured to quit after last window is closed.
+        if (!config.@"quit-after-last-window-closed") return;
+
+        // If a delay is configured, set a timeout function to quit after the delay.
+        if (config.@"quit-after-last-window-closed-delay") |v| {
+            priv.quit_timer = .{
+                .active = glib.timeoutAdd(
+                    v.asMilliseconds(),
+                    handleQuitTimerExpired,
+                    self,
+                ),
+            };
+        } else {
+            // If no delay is configured, treat it as expired.
+            priv.quit_timer = .expired;
+        }
+    }
+
+    /// This will get called when a new surface gets opened.
+    fn stopQuitTimer(self: *Self) void {
+        const priv = self.private();
+        switch (priv.quit_timer) {
+            .off => {},
+            .expired => priv.quit_timer = .off,
+            .active => |source| {
+                if (glib.Source.remove(source) == 0) {
+                    log.warn(
+                        "unable to remove quit timer source={d}",
+                        .{source},
+                    );
+                }
+
+                priv.quit_timer = .off;
+            },
+        }
+    }
+
     //---------------------------------------------------------------
     // Libghostty Callbacks
 
@@ -744,6 +848,20 @@ pub const Application = extern struct {
     //---------------------------------------------------------------
     // Signal Handlers
 
+    fn handleCloseConfirmation(
+        _: *CloseConfirmationDialog,
+        self: *Self,
+    ) callconv(.c) void {
+        self.quitNow();
+    }
+
+    fn handleQuitTimerExpired(ud: ?*anyopaque) callconv(.c) c_int {
+        const self: *Self = @ptrCast(@alignCast(ud));
+        const priv = self.private();
+        priv.quit_timer = .expired;
+        return 0;
+    }
+
     fn handleStyleManagerDark(
         style: *adw.StyleManager,
         _: *gobject.ParamSpec,
@@ -967,14 +1085,9 @@ const Action = struct {
         self: *Application,
         mode: apprt.action.QuitTimer,
     ) !void {
-        // TODO: An actual quit timer implementation. For now, we immediately
-        // quit on no windows regardless of the config.
         switch (mode) {
-            .start => {
-                self.private().running = false;
-            },
-
-            .stop => {},
+            .start => self.startQuitTimer(),
+            .stop => self.stopQuitTimer(),
         }
     }
 
diff --git a/src/apprt/gtk-ng/class/close_confirmation_dialog.zig b/src/apprt/gtk-ng/class/close_confirmation_dialog.zig
new file mode 100644
index 000000000..a5c6a3c22
--- /dev/null
+++ b/src/apprt/gtk-ng/class/close_confirmation_dialog.zig
@@ -0,0 +1,200 @@
+const std = @import("std");
+const adw = @import("adw");
+const gobject = @import("gobject");
+const gtk = @import("gtk");
+
+const gresource = @import("../build/gresource.zig");
+const i18n = @import("../../../os/main.zig").i18n;
+const adw_version = @import("../adw_version.zig");
+const Common = @import("../class.zig").Common;
+const Config = @import("config.zig").Config;
+const Dialog = @import("dialog.zig").Dialog;
+
+const log = std.log.scoped(.gtk_ghostty_config_errors_dialog);
+
+pub const CloseConfirmationDialog = extern struct {
+    const Self = @This();
+    parent_instance: Parent,
+    pub const Parent = Dialog;
+    pub const getGObjectType = gobject.ext.defineClass(Self, .{
+        .name = "GhosttyCloseConfirmationDialog",
+        .instanceInit = &init,
+        .classInit = &Class.init,
+        .parent_class = &Class.parent,
+        .private = .{ .Type = Private, .offset = &Private.offset },
+    });
+
+    pub const properties = struct {
+        pub const target = struct {
+            pub const name = "target";
+            const impl = gobject.ext.defineProperty(
+                name,
+                Self,
+                Target,
+                .{
+                    .nick = "Target",
+                    .blurb = "The target for this close confirmation.",
+                    .default = .app,
+                    .accessor = gobject.ext.privateFieldAccessor(
+                        Self,
+                        Private,
+                        &Private.offset,
+                        "target",
+                    ),
+                },
+            );
+        };
+    };
+
+    pub const signals = struct {
+        pub const @"close-request" = struct {
+            pub const name = "close-request";
+            pub const connect = impl.connect;
+            const impl = gobject.ext.defineSignal(
+                name,
+                Self,
+                &.{},
+                void,
+            );
+        };
+    };
+
+    const Private = struct {
+        target: Target,
+        pub var offset: c_int = 0;
+    };
+
+    pub fn new(target: Target) *Self {
+        return gobject.ext.newInstance(Self, .{
+            .target = target,
+        });
+    }
+
+    fn init(self: *Self, _: *Class) callconv(.C) void {
+        gtk.Widget.initTemplate(self.as(gtk.Widget));
+
+        // Setup our title/body text.
+        const priv = self.private();
+        self.as(Dialog.Parent).setHeading(priv.target.title());
+        self.as(Dialog.Parent).setBody(priv.target.body());
+    }
+
+    pub fn present(self: *Self) void {
+        const priv = self.private();
+        self.as(Dialog).present(priv.target.dialogParent());
+    }
+
+    pub fn close(self: *Self) void {
+        self.as(Dialog).close();
+    }
+
+    fn response(
+        self: *Self,
+        response_id: [*:0]const u8,
+    ) callconv(.C) void {
+        if (std.mem.orderZ(u8, response_id, "close") != .eq) return;
+        signals.@"close-request".impl.emit(
+            self,
+            null,
+            .{},
+            null,
+        );
+    }
+
+    fn dispose(self: *Self) callconv(.C) void {
+        gtk.Widget.disposeTemplate(
+            self.as(gtk.Widget),
+            getGObjectType(),
+        );
+
+        gobject.Object.virtual_methods.dispose.call(
+            Class.parent,
+            self.as(Parent),
+        );
+    }
+
+    const C = Common(Self, Private);
+    pub const as = C.as;
+    pub const ref = C.ref;
+    pub const unref = C.unref;
+    const private = C.private;
+
+    pub const Class = extern struct {
+        parent_class: Parent.Class,
+        var parent: *Parent.Class = undefined;
+        pub const Instance = Self;
+
+        fn init(class: *Class) callconv(.C) void {
+            gobject.ext.ensureType(Dialog);
+            gtk.Widget.Class.setTemplateFromResource(
+                class.as(gtk.Widget.Class),
+                comptime gresource.blueprint(.{
+                    .major = 1,
+                    .minor = 2,
+                    .name = "close-confirmation-dialog",
+                }),
+            );
+
+            // Properties
+            gobject.ext.registerProperties(class, &.{
+                properties.target.impl,
+            });
+
+            // Signals
+            signals.@"close-request".impl.register(.{});
+
+            // Virtual methods
+            gobject.Object.virtual_methods.dispose.implement(class, &dispose);
+            Dialog.virtual_methods.response.implement(class, &response);
+        }
+
+        pub const as = C.Class.as;
+    };
+};
+
+/// The target of a close dialog.
+///
+/// This is here so that we can consolidate all logic related to
+/// prompting the user and closing windows/tabs/surfaces/etc.
+/// together into one struct that is the sole source of truth.
+pub const Target = enum(c_int) {
+    app,
+
+    pub fn title(self: Target) [*:0]const u8 {
+        return switch (self) {
+            .app => i18n._("Quit Ghostty?"),
+        };
+    }
+
+    pub fn body(self: Target) [*:0]const u8 {
+        return switch (self) {
+            .app => i18n._("All terminal sessions will be terminated."),
+        };
+    }
+
+    pub fn dialogParent(self: Target) ?*gtk.Widget {
+        return switch (self) {
+            .app => {
+                // Find the currently focused window.
+                const list = gtk.Window.listToplevels();
+                defer list.free();
+                const focused = list.findCustom(null, findActiveWindow);
+                return @ptrCast(@alignCast(focused.f_data));
+            },
+        };
+    }
+
+    pub const getGObjectType = gobject.ext.defineEnum(
+        Target,
+        .{ .name = "GhosttyCloseConfirmationDialogTarget" },
+    );
+};
+
+fn findActiveWindow(data: ?*const anyopaque, _: ?*const anyopaque) callconv(.c) c_int {
+    const window: *gtk.Window = @ptrCast(@alignCast(@constCast(data orelse return -1)));
+
+    // Confusingly, `isActive` returns 1 when active,
+    // but we want to return 0 to indicate equality.
+    // Abusing integers to be enums and booleans is a terrible idea, C.
+    return if (window.isActive() != 0) 0 else -1;
+}
diff --git a/src/apprt/gtk-ng/ui/1.2/close-confirmation-dialog.blp b/src/apprt/gtk-ng/ui/1.2/close-confirmation-dialog.blp
new file mode 100644
index 000000000..c2dcbadbd
--- /dev/null
+++ b/src/apprt/gtk-ng/ui/1.2/close-confirmation-dialog.blp
@@ -0,0 +1,10 @@
+using Gtk 4.0;
+// This is unused but if we remove it we get a blueprint-compiler error.
+using Adw 1;
+
+template $GhosttyCloseConfirmationDialog: $GhosttyDialog {
+  responses [
+    cancel: _("Cancel"),
+    close: _("Close") destructive,
+  ]
+}