diff --git a/src/browser/browser.zig b/src/browser/browser.zig
index 1e74a8a9..d8178cbb 100644
--- a/src/browser/browser.zig
+++ b/src/browser/browser.zig
@@ -46,12 +46,15 @@ const polyfill = @import("../polyfill/polyfill.zig");
 
 const log = std.log.scoped(.browser);
 
+const user_agent = "Lightpanda.io/1.0";
+
 // Browser is an instance of the browser.
 // You can create multiple browser instances.
 // A browser contains only one session.
 // TODO allow multiple sessions per browser.
 pub const Browser = struct {
     session: Session = undefined,
+    agent: []const u8 = user_agent,
 
     const uri = "about:blank";
 
@@ -111,7 +114,7 @@ pub const Session = struct {
             .uri = uri,
             .alloc = alloc,
             .arena = std.heap.ArenaAllocator.init(alloc),
-            .window = Window.create(null),
+            .window = Window.create(null, .{ .agent = user_agent }),
             .loader = Loader.init(alloc),
             .storageShed = storage.Shed.init(alloc),
             .httpClient = undefined,
diff --git a/src/html/html.zig b/src/html/html.zig
index 3161e694..2bb439d1 100644
--- a/src/html/html.zig
+++ b/src/html/html.zig
@@ -21,6 +21,7 @@ const generate = @import("../generate.zig");
 const HTMLDocument = @import("document.zig").HTMLDocument;
 const HTMLElem = @import("elements.zig");
 const Window = @import("window.zig").Window;
+const Navigator = @import("navigator.zig").Navigator;
 
 pub const Interfaces = generate.Tuple(.{
     HTMLDocument,
@@ -28,4 +29,5 @@ pub const Interfaces = generate.Tuple(.{
     HTMLElem.HTMLMediaElement,
     HTMLElem.Interfaces,
     Window,
+    Navigator,
 });
diff --git a/src/html/navigator.zig b/src/html/navigator.zig
new file mode 100644
index 00000000..15253593
--- /dev/null
+++ b/src/html/navigator.zig
@@ -0,0 +1,56 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("netsurf");
+const jsruntime = @import("jsruntime");
+const Callback = jsruntime.Callback;
+const CallbackArg = jsruntime.CallbackArg;
+const Loop = jsruntime.Loop;
+
+const Case = jsruntime.test_utils.Case;
+const checkCases = jsruntime.test_utils.checkCases;
+
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+
+const storage = @import("../storage/storage.zig");
+
+// https://html.spec.whatwg.org/multipage/system-state.html#navigator
+pub const Navigator = struct {
+    pub const mem_guarantied = true;
+
+    agent: []const u8 = "",
+
+    pub fn get_userAgent(self: *Navigator) []const u8 {
+        return self.agent;
+    }
+};
+
+// Tests
+// -----
+
+pub fn testExecFn(
+    _: std.mem.Allocator,
+    js_env: *jsruntime.Env,
+) anyerror!void {
+    var navigator = [_]Case{
+        .{ .src = "navigator.userAgent", .ex = "" },
+    };
+    try checkCases(js_env, &navigator);
+}
diff --git a/src/html/window.zig b/src/html/window.zig
index b81c91ba..414b660d 100644
--- a/src/html/window.zig
+++ b/src/html/window.zig
@@ -25,6 +25,7 @@ const CallbackArg = jsruntime.CallbackArg;
 const Loop = jsruntime.Loop;
 
 const EventTarget = @import("../dom/event_target.zig").EventTarget;
+const Navigator = @import("navigator.zig").Navigator;
 
 const storage = @import("../storage/storage.zig");
 
@@ -48,9 +49,12 @@ pub const Window = struct {
     timeoutid: u32 = 0,
     timeoutids: [512]u64 = undefined,
 
-    pub fn create(target: ?[]const u8) Window {
+    navigator: Navigator,
+
+    pub fn create(target: ?[]const u8, navigator: ?Navigator) Window {
         return Window{
             .target = target orelse "",
+            .navigator = navigator orelse .{},
         };
     }
 
@@ -66,6 +70,10 @@ pub const Window = struct {
         return self;
     }
 
+    pub fn get_navigator(self: *Window) *Navigator {
+        return &self.navigator;
+    }
+
     pub fn get_self(self: *Window) *Window {
         return self;
     }
diff --git a/src/run_tests.zig b/src/run_tests.zig
index b506e5aa..077e56e2 100644
--- a/src/run_tests.zig
+++ b/src/run_tests.zig
@@ -96,7 +96,7 @@ fn testExecFn(
     });
 
     // alias global as self and window
-    var window = Window.create(null);
+    var window = Window.create(null, null);
 
     window.replaceDocument(doc);
     window.setStorageShelf(&storageShelf);
@@ -137,6 +137,7 @@ fn testsAllExecFn(
         HTMLElementTestExecFn,
         MutationObserverTestExecFn,
         @import("polyfill/fetch.zig").testExecFn,
+        @import("html/navigator.zig").testExecFn,
     };
 
     inline for (testFns) |testFn| {
@@ -359,7 +360,7 @@ test "bug document html parsing #4" {
 }
 
 test "Window is a libdom event target" {
-    var window = Window.create(null);
+    var window = Window.create(null, null);
 
     const event = try parser.eventCreate();
     try parser.eventInit(event, "foo", .{});
diff --git a/src/wpt/run.zig b/src/wpt/run.zig
index 07c3f740..208078b9 100644
--- a/src/wpt/run.zig
+++ b/src/wpt/run.zig
@@ -90,7 +90,7 @@ pub fn run(arena: *std.heap.ArenaAllocator, comptime dir: []const u8, f: []const
     }
 
     // setup global env vars.
-    var window = Window.create(null);
+    var window = Window.create(null, null);
     window.replaceDocument(html_doc);
     window.setStorageShelf(&storageShelf);
     try js_env.bindGlobal(&window);