diff --git a/src/Discord.Net.Rest/API/Rest/UploadWebhookFileParams.cs b/src/Discord.Net.Rest/API/Rest/UploadWebhookFileParams.cs
index 479a7857a..26153c21b 100644
--- a/src/Discord.Net.Rest/API/Rest/UploadWebhookFileParams.cs
+++ b/src/Discord.Net.Rest/API/Rest/UploadWebhookFileParams.cs
@@ -22,6 +22,8 @@ namespace Discord.API.Rest
         public Optional<string> AvatarUrl { get; set; }
         public Optional<Embed[]> Embeds { get; set; }
 
+        public bool IsSpoiler { get; set; } = false;
+
         public UploadWebhookFileParams(Stream file)
         {
             File = file;
@@ -30,7 +32,11 @@ namespace Discord.API.Rest
         public IReadOnlyDictionary<string, object> ToDictionary()
         {
             var d = new Dictionary<string, object>();
-            d["file"] = new MultipartFile(File, Filename.GetValueOrDefault("unknown.dat"));
+            var filename = Filename.GetValueOrDefault("unknown.dat");
+            if (IsSpoiler && !filename.StartsWith(AttachmentExtensions.SpoilerPrefix))
+                filename = filename.Insert(0, AttachmentExtensions.SpoilerPrefix);
+
+            d["file"] = new MultipartFile(File, filename);
 
             var payload = new Dictionary<string, object>();
             if (Content.IsSpecified)
diff --git a/src/Discord.Net.Webhook/DiscordWebhookClient.cs b/src/Discord.Net.Webhook/DiscordWebhookClient.cs
index 16841e936..ce2b45194 100644
--- a/src/Discord.Net.Webhook/DiscordWebhookClient.cs
+++ b/src/Discord.Net.Webhook/DiscordWebhookClient.cs
@@ -71,13 +71,13 @@ namespace Discord.Webhook
         /// <summary> Sends a message to the channel for this webhook with an attachment. </summary>
         /// <returns> Returns the ID of the created message. </returns>
         public Task<ulong> SendFileAsync(string filePath, string text, bool isTTS = false,
-            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null, RequestOptions options = null)
-            => WebhookClientHelper.SendFileAsync(this, filePath, text, isTTS, embeds, username, avatarUrl, options);
+            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null, RequestOptions options = null, bool isSpoiler = false)
+            => WebhookClientHelper.SendFileAsync(this, filePath, text, isTTS, embeds, username, avatarUrl, options, isSpoiler);
         /// <summary> Sends a message to the channel for this webhook with an attachment. </summary>
         /// <returns> Returns the ID of the created message. </returns>
         public Task<ulong> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false,
-            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null, RequestOptions options = null)
-            => WebhookClientHelper.SendFileAsync(this, stream, filename, text, isTTS, embeds, username, avatarUrl, options);
+            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null, RequestOptions options = null, bool isSpoiler = false)
+            => WebhookClientHelper.SendFileAsync(this, stream, filename, text, isTTS, embeds, username, avatarUrl, options, isSpoiler);
 
         /// <summary> Modifies the properties of this webhook. </summary>
         public Task ModifyWebhookAsync(Action<WebhookProperties> func, RequestOptions options = null)
diff --git a/src/Discord.Net.Webhook/WebhookClientHelper.cs b/src/Discord.Net.Webhook/WebhookClientHelper.cs
index a02cb3e2f..311d58bda 100644
--- a/src/Discord.Net.Webhook/WebhookClientHelper.cs
+++ b/src/Discord.Net.Webhook/WebhookClientHelper.cs
@@ -35,16 +35,16 @@ namespace Discord.Webhook
             return model.Id;
         }
         public static async Task<ulong> SendFileAsync(DiscordWebhookClient client, string filePath, string text, bool isTTS, 
-            IEnumerable<Embed> embeds, string username, string avatarUrl, RequestOptions options)
+            IEnumerable<Embed> embeds, string username, string avatarUrl, RequestOptions options, bool isSpoiler)
         {
             string filename = Path.GetFileName(filePath);
             using (var file = File.OpenRead(filePath))
-                return await SendFileAsync(client, file, filename, text, isTTS, embeds, username, avatarUrl, options).ConfigureAwait(false);
+                return await SendFileAsync(client, file, filename, text, isTTS, embeds, username, avatarUrl, options, isSpoiler).ConfigureAwait(false);
         }
         public static async Task<ulong> SendFileAsync(DiscordWebhookClient client, Stream stream, string filename, string text, bool isTTS,
-            IEnumerable<Embed> embeds, string username, string avatarUrl, RequestOptions options)
+            IEnumerable<Embed> embeds, string username, string avatarUrl, RequestOptions options, bool isSpoiler)
         {
-            var args = new UploadWebhookFileParams(stream) { Filename = filename, Content = text, IsTTS = isTTS };
+            var args = new UploadWebhookFileParams(stream) { Filename = filename, Content = text, IsTTS = isTTS, IsSpoiler = isSpoiler };
             if (username != null)
                 args.Username = username;
             if (avatarUrl != null)