diff --git a/CHANGELOG.md b/CHANGELOG.md
index f91d1db4..c6f9de1e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Release History
 
+## 2.0.0-beta.6 (Unreleased)
+
+## Bugs Fixed
+
+- ([#72](https://github.com/openai/openai-dotnet/issues/72)) Fixed `filename` request encoding in operations using `multipart/form-data`, including `files` and `audio`
+
 ## 2.0.0-beta.5 (2024-06-14)
 
 ## Features Added
diff --git a/src/Utility/MultipartFormDataBinaryContent.cs b/src/Utility/MultipartFormDataBinaryContent.cs
index 7a31f110..a1d04afd 100644
--- a/src/Utility/MultipartFormDataBinaryContent.cs
+++ b/src/Utility/MultipartFormDataBinaryContent.cs
@@ -34,19 +34,18 @@ public string ContentType
 
     internal HttpContent HttpContent => _multipartContent;
 
-    public void Add(Stream content, string name, string fileName = default, string contentType = null)
+    public void Add(Stream stream, string name, string fileName = default, string contentType = null)
     {
-        Argument.AssertNotNull(content, nameof(content));
-        Argument.AssertNotNullOrEmpty(name, nameof(name));
+        Argument.AssertNotNull(stream, nameof(stream));
 
-        Add(new StreamContent(content), name, fileName, contentType);
+        StreamContent content = new(stream);
+        if (contentType is not null)
+        {
+            content.Headers.ContentType = MediaTypeHeaderValue.Parse(contentType);
+        }
+        Add(content, name, fileName);
     }
 
-    //public void Add(Stream stream, string name, string fileName = default)
-    //{
-    //    Add(new StreamContent(stream), name, fileName);
-    //}
-
     public void Add(string content, string name, string fileName = default)
     {
         Add(new StringContent(content), name, fileName);
@@ -76,48 +75,19 @@ public void Add(BinaryData content, string name, string fileName = default)
         Add(new ByteArrayContent(content.ToArray()), name, fileName);
     }
 
-    private void Add(HttpContent content, string name, string filename, string contentType)
-    {
-        if (filename != null)
-        {
-            Argument.AssertNotNullOrEmpty(filename, nameof(filename));
-            AddFileNameHeader(content, name, filename);
-        }
-        if (contentType != null)
-        {
-            Argument.AssertNotNullOrEmpty(contentType, nameof(contentType));
-            AddContentTypeHeader(content, contentType);
-        }
-        _multipartContent.Add(content, name);
-    }
-
     private void Add(HttpContent content, string name, string fileName)
     {
+        Argument.AssertNotNull(content, nameof(content));
+        Argument.AssertNotNull(name, nameof(name));
+
         if (fileName is not null)
         {
-            AddFileNameHeader(content, name, fileName);
+            _multipartContent.Add(content, name, fileName);
         }
-
-        _multipartContent.Add(content, name);
-    }
-
-    private static void AddFileNameHeader(HttpContent content, string name, string filename)
-    {
-        // Add the content header manually because the default implementation
-        // adds a `filename*` parameter to the header, which RFC 7578 says not
-        // to do.  We are following up with the BCL team per correctness.
-        ContentDispositionHeaderValue header = new("form-data")
+        else
         {
-            Name = name,
-            FileName = filename
-        };
-        content.Headers.ContentDisposition = header;
-    }
-
-    public static void AddContentTypeHeader(HttpContent content, string contentType)
-    {
-        MediaTypeHeaderValue header = new MediaTypeHeaderValue(contentType);
-        content.Headers.ContentType = header;
+            _multipartContent.Add(content, name);
+        }
     }
 
 #if NET6_0_OR_GREATER
diff --git a/tests/Files/FileTests.cs b/tests/Files/FileTests.cs
index d42421f2..2f11a632 100644
--- a/tests/Files/FileTests.cs
+++ b/tests/Files/FileTests.cs
@@ -83,5 +83,17 @@ public void SerializeFileCollection()
         // TODO: Add this test.
     }
 
+    [Test]
+    public async Task NonAsciiFilename()
+    {
+        FileClient client = GetTestClient();
+        string filename = "你好.txt";
+        BinaryData fileContent = BinaryData.FromString("世界您好！这是个测试。");
+        OpenAIFileInfo uploadedFile = IsAsync
+            ? await client.UploadFileAsync(fileContent, filename, FileUploadPurpose.Assistants)
+            : client.UploadFile(fileContent, filename, FileUploadPurpose.Assistants);
+        Assert.That(uploadedFile?.Filename, Is.EqualTo(filename));
+    }
+
     private static FileClient GetTestClient() => GetTestClient<FileClient>(TestScenario.Files);
 }
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