diff --git a/src/FluentHttpClient.Tests/FluentTimeoutExtensionsTests.cs b/src/FluentHttpClient.Tests/FluentTimeoutExtensionsTests.cs
new file mode 100644
index 0000000..c2c5ce4
--- /dev/null
+++ b/src/FluentHttpClient.Tests/FluentTimeoutExtensionsTests.cs
@@ -0,0 +1,136 @@
+namespace FluentHttpClient.Tests;
+
+public class FluentTimeoutExtensionsTests
+{
+    private static HttpRequestBuilder CreateBuilder()
+    {
+        return new HttpRequestBuilder(new HttpClient(), "https://example.com");
+    }
+
+    public class ClearTimeout
+    {
+        [Fact]
+        public void ClearTimeout_SetsTimeoutToNull()
+        {
+            var builder = CreateBuilder()
+                .WithTimeout(60);
+
+            builder.Timeout.ShouldNotBeNull();
+            builder.Timeout.ShouldBe(TimeSpan.FromSeconds(60));
+
+            builder.ClearTimeout();
+
+            builder.Timeout.ShouldBeNull();
+        }
+    }
+
+    public class WithTimeout_Int
+    {
+        [Fact]
+        public void WithTimeout_SetsTimeoutFromSeconds_WhenValidSecondsProvided()
+        {
+            var builder = CreateBuilder()
+                .WithTimeout(30);
+
+            builder.Timeout.ShouldNotBeNull();
+            builder.Timeout.ShouldBe(TimeSpan.FromSeconds(30));
+        }
+
+        [Fact]
+        public void WithTimeout_ThrowsArgumentOutOfRangeException_WhenSecondsIsZero()
+        {
+            var builder = CreateBuilder();
+
+            var exception = Should.Throw<ArgumentOutOfRangeException>(() => builder.WithTimeout(0));
+
+            exception.ParamName.ShouldBe("seconds");
+            exception.Message.ShouldContain(FluentTimeoutExtensions.MessageInvalidTimeout);
+        }
+
+        [Fact]
+        public void WithTimeout_ThrowsArgumentOutOfRangeException_WhenSecondsIsNegative()
+        {
+            var builder = CreateBuilder();
+
+            var exception = Should.Throw<ArgumentOutOfRangeException>(() => builder.WithTimeout(-1));
+
+            exception.ParamName.ShouldBe("seconds");
+            exception.Message.ShouldContain(FluentTimeoutExtensions.MessageInvalidTimeout);
+        }
+
+        [Fact]
+        public void WithTimeout_OverwritesPreviousTimeout_WhenCalledMultipleTimes()
+        {
+            var builder = CreateBuilder();
+
+            builder.WithTimeout(10);
+            builder.Timeout.ShouldBe(TimeSpan.FromSeconds(10));
+
+            builder.WithTimeout(20);
+            builder.Timeout.ShouldBe(TimeSpan.FromSeconds(20));
+        }
+    }
+
+    public class WithTimeout_TimeSpan
+    {
+        [Fact]
+        public void WithTimeout_SetsTimeoutFromTimeSpan_WhenValidTimeSpanProvided()
+        {
+            var builder = CreateBuilder();
+            var timeout = TimeSpan.FromMinutes(2);
+
+            builder.WithTimeout(timeout);
+
+            builder.Timeout.ShouldNotBeNull();
+            builder.Timeout.ShouldBe(timeout);
+        }
+
+        [Fact]
+        public void WithTimeout_ThrowsArgumentOutOfRangeException_WhenTimeSpanIsZero()
+        {
+            var builder = CreateBuilder();
+
+            var exception = Should.Throw<ArgumentOutOfRangeException>(
+                () => builder.WithTimeout(TimeSpan.Zero));
+
+            exception.ParamName.ShouldBe("timeout");
+            exception.Message.ShouldContain(FluentTimeoutExtensions.MessageInvalidTimeout);
+        }
+
+        [Fact]
+        public void WithTimeout_ThrowsArgumentOutOfRangeException_WhenTimeSpanIsNegative()
+        {
+            var builder = CreateBuilder();
+
+            var exception = Should.Throw<ArgumentOutOfRangeException>(
+                () => builder.WithTimeout(TimeSpan.FromSeconds(-10)));
+
+            exception.ParamName.ShouldBe("timeout");
+            exception.Message.ShouldContain(FluentTimeoutExtensions.MessageInvalidTimeout);
+        }
+
+        [Fact]
+        public void WithTimeout_OverwritesPreviousTimeout_WhenCalledMultipleTimesWithTimeSpan()
+        {
+            var builder = CreateBuilder();
+
+            builder.WithTimeout(TimeSpan.FromSeconds(10));
+            builder.WithTimeout(TimeSpan.FromMinutes(5));
+
+            builder.Timeout.ShouldBe(TimeSpan.FromMinutes(5));
+        }
+
+        [Fact]
+        public void WithTimeout_SupportsMillisecondPrecision()
+        {
+            var builder = CreateBuilder();
+            var timeout = TimeSpan.FromMilliseconds(1500);
+
+            builder.WithTimeout(timeout);
+
+            builder.Timeout.ShouldBe(timeout);
+            builder.Timeout!.Value.TotalMilliseconds.ShouldBe(1500);
+        }
+    }
+}
+
diff --git a/src/FluentHttpClient.Tests/HttpRequestBuilderTests.cs b/src/FluentHttpClient.Tests/HttpRequestBuilderTests.cs
index 82e89a1..8521ab9 100644
--- a/src/FluentHttpClient.Tests/HttpRequestBuilderTests.cs
+++ b/src/FluentHttpClient.Tests/HttpRequestBuilderTests.cs
@@ -156,6 +156,40 @@ public void Cookies_HeaderConfigurators_And_OptionConfigurators_AreInitialized()
             builder.HeaderConfigurators.ShouldNotBeNull();
             builder.OptionConfigurators.ShouldNotBeNull();
         }
+
+        [Fact]
+        public void Timeout_IsNull_ByDefault()
+        {
+            using var client = CreateClient();
+
+            var builder = new HttpRequestBuilder(client);
+
+            builder.Timeout.ShouldBeNull();
+        }
+
+        [Fact]
+        public void Timeout_CanBeSet_WithValidTimeSpan()
+        {
+            using var client = CreateClient();
+            var builder = new HttpRequestBuilder(client);
+            var timeout = TimeSpan.FromSeconds(30);
+
+            builder.Timeout = timeout;
+
+            builder.Timeout.ShouldBe(timeout);
+        }
+
+        [Fact]
+        public void Timeout_CanBeCleared_BySettingToNull()
+        {
+            using var client = CreateClient();
+            var builder = new HttpRequestBuilder(client);
+            builder.Timeout = TimeSpan.FromSeconds(30);
+
+            builder.Timeout = null;
+
+            builder.Timeout.ShouldBeNull();
+        }
     }
 
     public class DeferredConfiguratorTests
@@ -845,4 +879,183 @@ public async Task SendAsync_ThrowsArgumentException_WhenMethodIsEmpty()
         }
     }
 
+    public class SendAsyncTimeoutTests
+    {
+        private sealed class DelayedHttpMessageHandler : HttpMessageHandler
+        {
+            private readonly TimeSpan _delay;
+            private readonly HttpStatusCode _statusCode;
+
+            public DelayedHttpMessageHandler(TimeSpan delay, HttpStatusCode statusCode = HttpStatusCode.OK)
+            {
+                _delay = delay;
+                _statusCode = statusCode;
+            }
+
+            public int CallCount { get; private set; }
+
+            public CancellationToken LastCancellationToken { get; private set; }
+
+            protected override async Task<HttpResponseMessage> SendAsync(
+                HttpRequestMessage request,
+                CancellationToken cancellationToken)
+            {
+                CallCount++;
+                LastCancellationToken = cancellationToken;
+
+                await Task.Delay(_delay, cancellationToken);
+
+                return new HttpResponseMessage(_statusCode);
+            }
+        }
+
+        [Fact]
+        public async Task SendAsync_DoesNotTimeout_WhenTimeoutIsNotSet()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromMilliseconds(50));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+
+            var response = await builder.SendAsync(HttpMethod.Get);
+
+            response.ShouldNotBeNull();
+            handler.CallCount.ShouldBe(1);
+        }
+
+        [Fact]
+        public async Task SendAsync_CompletesSuccessfully_WhenRequestCompletesBeforeTimeout()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromMilliseconds(50));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromSeconds(5);
+
+            var response = await builder.SendAsync(HttpMethod.Get);
+
+            response.ShouldNotBeNull();
+            response.StatusCode.ShouldBe(HttpStatusCode.OK);
+            handler.CallCount.ShouldBe(1);
+        }
+
+        [Fact]
+        public async Task SendAsync_ThrowsTaskCanceledException_WhenRequestExceedsTimeout()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromSeconds(10));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromMilliseconds(100);
+
+            await Should.ThrowAsync<TaskCanceledException>(
+                async () => await builder.SendAsync(HttpMethod.Get));
+
+            handler.CallCount.ShouldBe(1);
+        }
+
+        [Fact]
+        public async Task SendAsync_UsesLinkedCancellationToken_WhenTimeoutIsSet()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromMilliseconds(50));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromSeconds(5);
+
+            using var cts = new CancellationTokenSource();
+
+            var response = await builder.SendAsync(HttpMethod.Get, cts.Token);
+
+            response.ShouldNotBeNull();
+            handler.CallCount.ShouldBe(1);
+            handler.LastCancellationToken.ShouldNotBe(cts.Token);
+        }
+
+        [Fact]
+        public async Task SendAsync_CancelsImmediately_WhenCallerTokenIsAlreadyCanceled()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromSeconds(10));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromSeconds(5);
+
+            using var cts = new CancellationTokenSource();
+            cts.Cancel();
+
+            await Should.ThrowAsync<TaskCanceledException>(
+                async () => await builder.SendAsync(HttpMethod.Get, cts.Token));
+        }
+
+        [Fact]
+        public async Task SendAsync_CompletesSuccessfully_WhenTimeoutIsNull()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromMilliseconds(50));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = null;
+
+            using var cts = new CancellationTokenSource();
+
+            var response = await builder.SendAsync(HttpMethod.Get, cts.Token);
+
+            response.ShouldNotBeNull();
+            response.StatusCode.ShouldBe(HttpStatusCode.OK);
+            handler.CallCount.ShouldBe(1);
+        }
+
+        [Fact]
+        public async Task SendAsync_RespectsTimeoutAcrossMultipleRequests()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromMilliseconds(50));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromSeconds(5);
+
+            var response1 = await builder.SendAsync(HttpMethod.Get);
+            var response2 = await builder.SendAsync(HttpMethod.Get);
+
+            response1.ShouldNotBeNull();
+            response2.ShouldNotBeNull();
+            handler.CallCount.ShouldBe(2);
+        }
+
+        [Fact]
+        public async Task SendAsync_CanCancelViaTimeout_EvenWithLongerCallerTimeout()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromSeconds(10));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromMilliseconds(100);
+
+            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+
+            await Should.ThrowAsync<TaskCanceledException>(
+                async () => await builder.SendAsync(HttpMethod.Get, cts.Token));
+
+            handler.CallCount.ShouldBe(1);
+        }
+
+        [Fact]
+        public async Task SendAsync_CanCancelViaCallerToken_EvenWithLongerBuilderTimeout()
+        {
+            var handler = new DelayedHttpMessageHandler(TimeSpan.FromSeconds(10));
+            using var client = new HttpClient(handler) { BaseAddress = new Uri("https://api.example.com/") };
+
+            var builder = new HttpRequestBuilder(client, "items");
+            builder.Timeout = TimeSpan.FromSeconds(30);
+
+            using var cts = new CancellationTokenSource(TimeSpan.FromMilliseconds(100));
+
+            await Should.ThrowAsync<TaskCanceledException>(
+                async () => await builder.SendAsync(HttpMethod.Get, cts.Token));
+
+            handler.CallCount.ShouldBe(1);
+        }
+    }
+
 }
diff --git a/src/FluentHttpClient/FluentTimeoutExtensions.cs b/src/FluentHttpClient/FluentTimeoutExtensions.cs
index 272b8f8..9ad8740 100644
--- a/src/FluentHttpClient/FluentTimeoutExtensions.cs
+++ b/src/FluentHttpClient/FluentTimeoutExtensions.cs
@@ -7,6 +7,17 @@ public static class FluentTimeoutExtensions
 {
     internal static readonly string MessageInvalidTimeout = "Timeout must be a positive value.";
 
+    /// <summary>
+    /// Clears any per-request timeout that has been set.
+    /// </summary>
+    /// <param name="builder"></param>
+    /// <returns></returns>
+    public static HttpRequestBuilder ClearTimeout(this HttpRequestBuilder builder)
+    {
+        builder.Timeout = null;
+        return builder;
+    }
+
     /// <summary>
     /// Sets a per-request timeout using the specified number of seconds. Must be positive.
     /// </summary>