diff --git a/SteamKit2/SteamKit2/Steam/SteamClient/Configuration/SteamConfigurationBuilder.cs b/SteamKit2/SteamKit2/Steam/SteamClient/Configuration/SteamConfigurationBuilder.cs
index 82b0ef9b2..cdf502a71 100644
--- a/SteamKit2/SteamKit2/Steam/SteamClient/Configuration/SteamConfigurationBuilder.cs
+++ b/SteamKit2/SteamKit2/Steam/SteamClient/Configuration/SteamConfigurationBuilder.cs
@@ -6,6 +6,7 @@
 
 using System;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using SteamKit2.Discovery;
 
 namespace SteamKit2
@@ -107,6 +108,13 @@ public ISteamConfigurationBuilder WithWebAPIKey(string webApiKey)
             return this;
         }
 
-        static HttpClient DefaultHttpClientFactory() => new HttpClient();
+        static HttpClient DefaultHttpClientFactory()
+        {
+            var client = new HttpClient();
+
+            var assemblyVersion = typeof(SteamConfiguration).Assembly.GetName().Version.ToString(fieldCount: 3);
+            client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("SteamKit", assemblyVersion));
+            return client;
+        }
     }
 }
diff --git a/SteamKit2/Tests/SteamConfigurationFacts.cs b/SteamKit2/Tests/SteamConfigurationFacts.cs
index de5377aa4..38bbead69 100644
--- a/SteamKit2/Tests/SteamConfigurationFacts.cs
+++ b/SteamKit2/Tests/SteamConfigurationFacts.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
@@ -55,6 +56,9 @@ public void DefaultHttpClientFactory()
             {
                 Assert.NotNull(client);
                 Assert.IsType<HttpClient>(client);
+
+                var steamKitAssemblyVersion = typeof( SteamClient ).Assembly.GetName().Version;
+                Assert.Equal("SteamKit/" + steamKitAssemblyVersion.ToString(fieldCount: 3), client.DefaultRequestHeaders.UserAgent.ToString());
             }
         }