diff --git a/Storage/Extensions/HttpClientProgress.cs b/Storage/Extensions/HttpClientProgress.cs
index ddb57fd..4d423e2 100644
--- a/Storage/Extensions/HttpClientProgress.cs
+++ b/Storage/Extensions/HttpClientProgress.cs
@@ -20,6 +20,13 @@ namespace Supabase.Storage.Extensions
     /// </summary>
     internal static class HttpClientProgress
     {
+        /// <summary>
+        /// Buffer size for stream copies, matching the BCL's default <see cref="Stream.CopyTo(Stream)"/>
+        /// size (80 KB). Kept just under the 85,000-byte Large Object Heap threshold so the buffer
+        /// stays on the gen-0 heap. This is set to the default expected value.
+        /// </summary>
+        private const int CopyBufferSize = 81920;
+
         public static async Task<MemoryStream> DownloadDataAsync(
             this HttpClient client,
             Uri uri,
@@ -49,7 +56,8 @@ public static async Task<MemoryStream> DownloadDataAsync(
                 using (
                     var response = await client.SendAsync(
                         message,
-                        HttpCompletionOption.ResponseHeadersRead
+                        HttpCompletionOption.ResponseHeadersRead,
+                        cancellationToken
                     )
                 )
                 {
@@ -76,10 +84,9 @@ public static async Task<MemoryStream> DownloadDataAsync(
                     var contentLength = response.Content.Headers.ContentLength;
                     using (var download = await response.Content.ReadAsStreamAsync())
                     {
-                        // no progress... no contentLength... very sad
                         if (progress is null || !contentLength.HasValue)
                         {
-                            await download.CopyToAsync(destination);
+                            await download.CopyToAsync(destination, CopyBufferSize, cancellationToken);
                             return destination;
                         }
 
@@ -89,7 +96,7 @@ public static async Task<MemoryStream> DownloadDataAsync(
                         );
                         await download.CopyToAsync(
                             destination,
-                            81920,
+                            CopyBufferSize,
                             progressWrapper,
                             cancellationToken
                         );
diff --git a/Storage/Interfaces/IStorageFileApi.cs b/Storage/Interfaces/IStorageFileApi.cs
index 5cb3a17..9410d89 100644
--- a/Storage/Interfaces/IStorageFileApi.cs
+++ b/Storage/Interfaces/IStorageFileApi.cs
@@ -20,33 +20,38 @@ Task<string> CreateSignedUrl(
             int expiresIn,
             DownloadOptions? options = null
         );
-        Task<byte[]> Download(string supabasePath, EventHandler<float>? onProgress = null);
+        Task<byte[]> Download(string supabasePath, EventHandler<float>? onProgress = null, CancellationToken cancellationToken = default);
         Task<byte[]> Download(
             string supabasePath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         );
         Task<string> Download(
             string supabasePath,
             string localPath,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         );
         Task<string> Download(
             string supabasePath,
             string localPath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         );
         Task<byte[]> DownloadPublicFile(
             string supabasePath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         );
         Task<string> DownloadPublicFile(
             string supabasePath,
             string localPath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         );
         string GetPublicUrl(
             string path,
diff --git a/Storage/StorageFileApi.cs b/Storage/StorageFileApi.cs
index 4a66222..ed568f3 100644
--- a/Storage/StorageFileApi.cs
+++ b/Storage/StorageFileApi.cs
@@ -513,19 +513,21 @@ await Helpers.MakeRequest<GenericResponse>(
         /// <param name="localPath"></param>
         /// <param name="transformOptions"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
         public Task<string> Download(
             string supabasePath,
             string localPath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var url =
                 transformOptions != null
                     ? $"{Url}/render/image/authenticated/{GetFinalPath(supabasePath)}"
                     : $"{Url}/object/{GetFinalPath(supabasePath)}";
-            return DownloadFile(url, localPath, transformOptions, onProgress);
+            return DownloadFile(url, localPath, transformOptions, onProgress, cancellationToken);
         }
 
         /// <summary>
@@ -534,12 +536,14 @@ public Task<string> Download(
         /// <param name="supabasePath"></param>
         /// <param name="localPath"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
         public Task<string> Download(
             string supabasePath,
             string localPath,
-            EventHandler<float>? onProgress = null
-        ) => Download(supabasePath, localPath, null, onProgress: onProgress);
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
+        ) => Download(supabasePath, localPath, null, onProgress: onProgress, cancellationToken);
 
         /// <summary>
         /// Downloads a byte array from a private bucket to be used programmatically. For public buckets <see cref="DownloadPublicFile(string, TransformOptions?, EventHandler{float}?)"/>
@@ -547,15 +551,17 @@ public Task<string> Download(
         /// <param name="supabasePath"></param>
         /// <param name="transformOptions"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
         public Task<byte[]> Download(
             string supabasePath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var url = $"{Url}/object/{GetFinalPath(supabasePath)}";
-            return DownloadBytes(url, transformOptions, onProgress);
+            return DownloadBytes(url, transformOptions, onProgress, cancellationToken);
         }
 
         /// <summary>
@@ -563,9 +569,10 @@ public Task<byte[]> Download(
         /// </summary>
         /// <param name="supabasePath"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public Task<byte[]> Download(string supabasePath, EventHandler<float>? onProgress = null) =>
-            Download(supabasePath, transformOptions: null, onProgress: onProgress);
+        public Task<byte[]> Download(string supabasePath, EventHandler<float>? onProgress = null, CancellationToken cancellationToken = default) =>
+            Download(supabasePath, transformOptions: null, onProgress: onProgress, cancellationToken);
 
         /// <summary>
         /// Downloads a public file to the filesystem. This method DOES NOT VERIFY that the file is actually public.
@@ -574,16 +581,18 @@ public Task<byte[]> Download(string supabasePath, EventHandler<float>? onProgres
         /// <param name="localPath"></param>
         /// <param name="transformOptions"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
         public Task<string> DownloadPublicFile(
             string supabasePath,
             string localPath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var url = GetPublicUrl(supabasePath, transformOptions);
-            return DownloadFile(url, localPath, transformOptions, onProgress);
+            return DownloadFile(url, localPath, transformOptions, onProgress, cancellationToken);
         }
 
         /// <summary>
@@ -592,15 +601,17 @@ public Task<string> DownloadPublicFile(
         /// <param name="supabasePath"></param>
         /// <param name="transformOptions"></param>
         /// <param name="onProgress"></param>
+        /// <param name="cancellationToken"></param>
         /// <returns></returns>
         public Task<byte[]> DownloadPublicFile(
             string supabasePath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var url = GetPublicUrl(supabasePath, transformOptions);
-            return DownloadBytes(url, transformOptions, onProgress);
+            return DownloadBytes(url, transformOptions, onProgress, cancellationToken);
         }
 
         /// <summary>
@@ -835,7 +846,8 @@ private async Task<string> DownloadFile(
             string url,
             string localPath,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var builder = new UriBuilder(url);
@@ -850,7 +862,8 @@ private async Task<string> DownloadFile(
             var stream = await Helpers.HttpDownloadClient!.DownloadDataAsync(
                 builder.Uri,
                 Headers,
-                progress
+                progress,
+                cancellationToken
             );
 
             using var fileStream = new FileStream(
@@ -867,7 +880,8 @@ private async Task<string> DownloadFile(
         private async Task<byte[]> DownloadBytes(
             string url,
             TransformOptions? transformOptions = null,
-            EventHandler<float>? onProgress = null
+            EventHandler<float>? onProgress = null,
+            CancellationToken cancellationToken = default
         )
         {
             var builder = new UriBuilder(url);
@@ -882,7 +896,8 @@ private async Task<byte[]> DownloadBytes(
             var stream = await Helpers.HttpDownloadClient!.DownloadDataAsync(
                 builder.Uri,
                 Headers,
-                progress
+                progress,
+                cancellationToken
             );
 
             return stream.ToArray();
diff --git a/StorageTests/Files/StorageFileDownloadCancellationTests.cs b/StorageTests/Files/StorageFileDownloadCancellationTests.cs
new file mode 100644
index 0000000..9635450
--- /dev/null
+++ b/StorageTests/Files/StorageFileDownloadCancellationTests.cs
@@ -0,0 +1,122 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Supabase.Storage;
+
+namespace StorageTests.Files;
+
+/// <summary>
+/// Contract tests pinning that the file API threads the caller's <see cref="CancellationToken"/> all
+/// the way through the download pipeline: onto the HTTP request itself, and onto the response-body copy
+/// on the chunked (no <c>Content-Length</c>) path that the progress-reporting branch never exercises.
+/// A stub <see cref="HttpMessageHandler"/> stands in for the download client, and each test observes the
+/// token *at the point under test* rather than relying on the thrown exception — the body copy honoured
+/// the token before these fixes too, so a bare "throws when cancelled" assertion cannot tell the fix
+/// apart from the pre-existing behaviour.
+/// </summary>
+[TestClass]
+[TestCategory("Contract")]
+public class StorageFileDownloadCancellationTests
+{
+    private const string Bucket = "bucket";
+
+    private Client client = null!;
+    private HttpClient? downloadClient;
+
+    [TestInitialize]
+    public void TestInitialize() =>
+        this.client = new Client("http://localhost/storage/v1", new Dictionary<string, string>
+        {
+            { "Authorization", "Bearer test-key" }
+        });
+
+    [TestCleanup]
+    public void TestCleanup() => this.downloadClient?.Dispose();
+
+    [TestMethod]
+    public async Task Download_ShouldForwardTheTokenToTheRequest()
+    {
+        using var cts = new CancellationTokenSource();
+        var requestSawLiveToken = false;
+        this.UseHandler(new StubHandler((_, token) =>
+        {
+            cts.Cancel();
+            requestSawLiveToken = token.IsCancellationRequested;
+            token.ThrowIfCancellationRequested();
+            return EmptyOk();
+        }));
+        var act = () => this.client.From(Bucket).Download("a.bin", onProgress: null, cts.Token);
+        await act.Should().ThrowAsync<OperationCanceledException>();
+        requestSawLiveToken.Should().BeTrue(
+            "the request must carry the caller's token so a stalled connection can be cancelled before any body arrives");
+    }
+
+    [TestMethod]
+    public async Task Download_ShouldHonorCancellation_GivenResponseWithoutContentLength()
+    {
+        using var cts = new CancellationTokenSource();
+        var bodyCopySawLiveToken = false;
+        var body = new TokenObservingStream(token =>
+        {
+            cts.Cancel();
+            bodyCopySawLiveToken = token.IsCancellationRequested;
+            token.ThrowIfCancellationRequested();
+        });
+        this.UseHandler(new StubHandler((_, _) =>
+            new HttpResponseMessage(HttpStatusCode.OK) { Content = new StreamContent(body) }));
+        var act = () => this.client.From(Bucket).Download("a.bin", onProgress: null, cts.Token);
+        await act.Should().ThrowAsync<OperationCanceledException>();
+        bodyCopySawLiveToken.Should().BeTrue(
+            "the body copy must carry the token even when the server omits Content-Length and no progress handler is supplied");
+    }
+
+    private void UseHandler(HttpMessageHandler handler) =>
+        Supabase.Storage.Helpers.HttpDownloadClient = this.downloadClient = new HttpClient(handler);
+
+    private static HttpResponseMessage EmptyOk() =>
+        new(HttpStatusCode.OK) { Content = new ByteArrayContent(Array.Empty<byte>()) };
+
+    private sealed class StubHandler(Func<HttpRequestMessage, CancellationToken, HttpResponseMessage> respond)
+        : HttpMessageHandler
+    {
+        protected override Task<HttpResponseMessage> SendAsync(
+            HttpRequestMessage request, CancellationToken cancellationToken) =>
+            Task.FromResult(respond(request, cancellationToken));
+    }
+
+    /// <summary>
+    /// A non-seekable response body (so the response carries no <c>Content-Length</c>) that reports the
+    /// token handed to each read back to the test before signalling end-of-stream.
+    /// </summary>
+    private sealed class TokenObservingStream(Action<CancellationToken> onRead) : Stream
+    {
+        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            onRead(cancellationToken);
+            return Task.FromResult(0);
+        }
+
+        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        {
+            onRead(cancellationToken);
+            return new ValueTask<int>(0);
+        }
+
+        public override bool CanRead => true;
+        public override bool CanSeek => false;
+        public override bool CanWrite => false;
+        public override long Length => throw new NotSupportedException();
+        public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
+        public override void Flush() { }
+        public override int Read(byte[] buffer, int offset, int count) => throw new NotSupportedException();
+        public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
+        public override void SetLength(long value) => throw new NotSupportedException();
+        public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
+    }
+}
diff --git a/StorageTests/Files/StorageFileTests.cs b/StorageTests/Files/StorageFileTests.cs
index 532d2ef..44ea248 100644
--- a/StorageTests/Files/StorageFileTests.cs
+++ b/StorageTests/Files/StorageFileTests.cs
@@ -192,6 +192,21 @@ public async Task Download_ShouldWriteFileToDisk()
         await this.bucket.Remove(new List<string> { name });
     }
 
+    [TestMethod]
+    public async Task Download_ShouldCancelAndLeaveNoFile_GivenCancelledToken()
+    {
+        using var cts = new CancellationTokenSource();
+        await cts.CancelAsync();
+        var name = $"{Guid.NewGuid()}.png";
+        var imagePath = Path.Combine(BasePath(), "Assets", "supabase-csharp.png");
+        await this.bucket.Upload(imagePath, name);
+        var downloadPath = Path.Combine(BasePath(), name);
+        var act = () => this.bucket.Download(name, downloadPath, null, cts.Token);
+        await act.Should().ThrowAsync<OperationCanceledException>();
+        File.Exists(downloadPath).Should().BeFalse();
+        await this.bucket.Remove(new List<string> { name });
+    }
+
     [TestMethod]
     public async Task Download_ShouldReturnTheStoredBytes()
     {