diff --git a/Libraries/Microsoft.Teams.Api/SignIn/StateVerifyQuery.cs b/Libraries/Microsoft.Teams.Api/SignIn/StateVerifyQuery.cs
index 66f877f9..c9cbf3c2 100644
--- a/Libraries/Microsoft.Teams.Api/SignIn/StateVerifyQuery.cs
+++ b/Libraries/Microsoft.Teams.Api/SignIn/StateVerifyQuery.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System.Text.Json;
 using System.Text.Json.Serialization;
 
 namespace Microsoft.Teams.Api.SignIn;
@@ -13,9 +14,49 @@ public class StateVerifyQuery
     /// <summary>
     /// The state string originally received when the
     /// signin web flow is finished with a state posted back to client via tab SDK
-    /// microsoftTeams.authentication.notifySuccess(state)
+    /// microsoftTeams.authentication.notifySuccess(state).
+    /// Can be either a string or a JSON object depending on the platform (Android/iOS may send objects).
+    /// When a JSON object is received, it is automatically serialized to a JSON string.
     /// </summary>
     [JsonPropertyName("state")]
     [JsonPropertyOrder(0)]
+    [JsonConverter(typeof(StringOrObjectConverter))]
     public string? State { get; set; }
+
+    /// <summary>
+    /// Custom JSON converter that handles both string and object values for the State property.
+    /// When deserializing, if the value is a string, it returns the string value.
+    /// If the value is a JSON object (or any other type), it serializes it to a JSON string.
+    /// </summary>
+    private class StringOrObjectConverter : JsonConverter<string?>
+    {
+        public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType == JsonTokenType.Null)
+            {
+                return null;
+            }
+
+            if (reader.TokenType == JsonTokenType.String)
+            {
+                return reader.GetString();
+            }
+
+            // For any other token type (object, array, number, etc.), read as JsonElement and serialize
+            using var doc = JsonDocument.ParseValue(ref reader);
+            return JsonSerializer.Serialize(doc.RootElement);
+        }
+
+        public override void Write(Utf8JsonWriter writer, string? value, JsonSerializerOptions options)
+        {
+            if (value == null)
+            {
+                writer.WriteNullValue();
+            }
+            else
+            {
+                writer.WriteStringValue(value);
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/Tests/Microsoft.Teams.Api.Tests/Activities/Invokes/SignIn/VerifyStateSignInActivityTests.cs b/Tests/Microsoft.Teams.Api.Tests/Activities/Invokes/SignIn/VerifyStateSignInActivityTests.cs
index 44d3a9a1..6164590d 100644
--- a/Tests/Microsoft.Teams.Api.Tests/Activities/Invokes/SignIn/VerifyStateSignInActivityTests.cs
+++ b/Tests/Microsoft.Teams.Api.Tests/Activities/Invokes/SignIn/VerifyStateSignInActivityTests.cs
@@ -147,4 +147,129 @@ public void setupSignInVerifyStateActivity_JsonDeserialize_Derived_Activity_Inte
         Assert.NotNull(activity);
         Assert.Equal(expected.ToString(), activity.ToString());
     }
+
+    [Fact]
+    public void setupSignInVerifyStateActivity_JsonDeserialize_StateAsObject()
+    {
+        // Test JSON with state as an object (Android/iOS scenario)
+        var jsonWithObjectState = @"{
+  ""type"": ""invoke"",
+  ""channelId"": ""msteams"",
+  ""name"": ""signin/verifyState"",
+  ""value"": {
+    ""state"": {
+      ""token"": ""abc123"",
+      ""userId"": ""user123""
+    }
+  },
+  ""from"": {
+    ""id"": ""botId"",
+    ""aadObjectId"": ""aadObjectId"",
+    ""name"": ""User Name""
+  },
+  ""recipient"": {
+    ""id"": ""recipientId"",
+    ""name"": ""Recipient Name""
+  },
+  ""conversation"": {
+    ""id"": ""conversationId"",
+    ""conversationType"": ""groupChat""
+  }
+}";
+
+        var activity = JsonSerializer.Deserialize<VerifyStateActivity>(jsonWithObjectState);
+
+        Assert.NotNull(activity);
+        Assert.NotNull(activity.Value);
+        Assert.NotNull(activity.Value.State);
+        
+        // Verify the state was serialized to a JSON string
+        Assert.Contains("token", activity.Value.State);
+        Assert.Contains("abc123", activity.Value.State);
+        Assert.Contains("userId", activity.Value.State);
+        Assert.Contains("user123", activity.Value.State);
+    }
+
+    [Fact]
+    public void setupSignInVerifyStateActivity_JsonDeserialize_StateAsObject_ViaSignInActivity()
+    {
+        // Test JSON with state as an object through SignInActivity
+        var jsonWithObjectState = @"{
+  ""type"": ""invoke"",
+  ""channelId"": ""msteams"",
+  ""name"": ""signin/verifyState"",
+  ""value"": {
+    ""state"": {
+      ""sessionId"": ""session-456"",
+      ""redirectUrl"": ""https://example.com/callback""
+    }
+  },
+  ""from"": {
+    ""id"": ""botId"",
+    ""aadObjectId"": ""aadObjectId"",
+    ""name"": ""User Name""
+  },
+  ""recipient"": {
+    ""id"": ""recipientId"",
+    ""name"": ""Recipient Name""
+  },
+  ""conversation"": {
+    ""id"": ""conversationId"",
+    ""conversationType"": ""groupChat""
+  }
+}";
+
+        var activity = JsonSerializer.Deserialize<SignInActivity>(jsonWithObjectState);
+
+        Assert.NotNull(activity);
+        var verifyStateActivity = activity.ToVerifyState();
+        Assert.NotNull(verifyStateActivity);
+        Assert.NotNull(verifyStateActivity.Value.State);
+        
+        // Verify the state was serialized to a JSON string
+        Assert.Contains("sessionId", verifyStateActivity.Value.State);
+        Assert.Contains("session-456", verifyStateActivity.Value.State);
+    }
+
+    [Fact]
+    public void setupSignInVerifyStateActivity_JsonDeserialize_StateAsObject_ViaActivity()
+    {
+        // Test JSON with state as an object through Activity
+        var jsonWithObjectState = @"{
+  ""type"": ""invoke"",
+  ""channelId"": ""msteams"",
+  ""name"": ""signin/verifyState"",
+  ""value"": {
+    ""state"": {
+      ""code"": ""auth-code-789""
+    }
+  },
+  ""from"": {
+    ""id"": ""botId"",
+    ""aadObjectId"": ""aadObjectId"",
+    ""name"": ""User Name""
+  },
+  ""recipient"": {
+    ""id"": ""recipientId"",
+    ""name"": ""Recipient Name""
+  },
+  ""conversation"": {
+    ""id"": ""conversationId"",
+    ""conversationType"": ""groupChat""
+  }
+}";
+
+        var activity = JsonSerializer.Deserialize<Activity>(jsonWithObjectState);
+
+        Assert.NotNull(activity);
+        Assert.True(activity is InvokeActivity);
+        var invokeActivity = (InvokeActivity)activity;
+        Assert.True(invokeActivity is SignInActivity);
+        var signInActivity = (SignInActivity)invokeActivity;
+        var verifyStateActivity = signInActivity.ToVerifyState();
+        
+        Assert.NotNull(verifyStateActivity.Value.State);
+        Assert.Contains("code", verifyStateActivity.Value.State);
+        Assert.Contains("auth-code-789", verifyStateActivity.Value.State);
+    }
 }
\ No newline at end of file