diff --git a/voice/src/vonage_voice/models/__init__.py b/voice/src/vonage_voice/models/__init__.py
index df81bace..a3661c98 100644
--- a/voice/src/vonage_voice/models/__init__.py
+++ b/voice/src/vonage_voice/models/__init__.py
@@ -42,11 +42,13 @@
     Embedded,
     HalLinks,
 )
+from .webhooks import AnswerWebhook
 
 __all__ = [
     "AdvancedMachineDetection",
     "AppEndpoint",
     "AudioStreamOptions",
+    "AnswerWebhook",
     "CallInfo",
     "CallList",
     "CallMessage",
diff --git a/voice/src/vonage_voice/models/webhooks.py b/voice/src/vonage_voice/models/webhooks.py
new file mode 100644
index 00000000..6fb84a1b
--- /dev/null
+++ b/voice/src/vonage_voice/models/webhooks.py
@@ -0,0 +1,36 @@
+from typing import Optional
+
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class AnswerWebhook(BaseModel):
+    """Model for the Voice API Answer webhook payload.
+
+    Args:
+        to (str, Optional): The number or endpoint that answered the call.
+        from_ (str, Optional): The number or endpoint that initiated the call.
+        from_user (str, Optional): The Client SDK user that initiated the call.
+        endpoint_type (str, Optional): The type of endpoint that answered the call.
+        uuid (str, Optional): The unique identifier for this call.
+        conversation_uuid (str, Optional): The unique identifier for this conversation.
+        region_url (str, Optional): Regional API endpoint to control the call.
+        custom_data (dict, Optional): Custom data object passed from the Client SDK.
+        sipheader_user_to_user (str, Optional): Content of the SIP User-to-User header,
+            received as the `SipHeader_User-to-User` parameter on the webhook.
+    """
+
+    model_config = ConfigDict(populate_by_name=True)
+
+    to: Optional[str] = None
+    from_: Optional[str] = Field(None, alias='from')
+    from_user: Optional[str] = None
+    endpoint_type: Optional[str] = None
+    uuid: Optional[str] = None
+    conversation_uuid: Optional[str] = None
+    region_url: Optional[str] = None
+    custom_data: Optional[dict] = None
+    sipheader_user_to_user: Optional[str] = Field(
+        None,
+        validation_alias='SipHeader_User-to-User',
+        serialization_alias='SipHeader_User-to-User',
+    )
diff --git a/voice/tests/test_answer_webhook.py b/voice/tests/test_answer_webhook.py
new file mode 100644
index 00000000..ab56057a
--- /dev/null
+++ b/voice/tests/test_answer_webhook.py
@@ -0,0 +1,24 @@
+from vonage_voice.models import AnswerWebhook
+
+
+def test_answer_webhook_sipheader_user_to_user_alias():
+    payload = {
+        'to': '442079460000',
+        'from': '447700900000',
+        'uuid': 'aaaaaaaa-bbbb-cccc-dddd-0123456789ab',
+        'conversation_uuid': 'CON-aaaaaaaa-bbbb-cccc-dddd-0123456789ab',
+        'SipHeader_User-to-User': '1234567890abcdef;encoding=hex',
+    }
+
+    hook = AnswerWebhook(**payload)
+
+    assert hook.to == '442079460000'
+    assert hook.from_ == '447700900000'
+    assert (
+        hook.sipheader_user_to_user == '1234567890abcdef;encoding=hex'
+    ), 'Field should be populated from SipHeader_User-to-User'
+
+    dumped = hook.model_dump(by_alias=True, exclude_none=True)
+    assert (
+        dumped['SipHeader_User-to-User'] == '1234567890abcdef;encoding=hex'
+    ), 'Field should serialize back with the SipHeader_User-to-User key'
diff --git a/voice/tests/test_voice.py b/voice/tests/test_voice.py
index 87253fb3..9e002111 100644
--- a/voice/tests/test_voice.py
+++ b/voice/tests/test_voice.py
@@ -4,6 +4,7 @@
 import responses
 from pytest import raises
 from responses.matchers import json_params_matcher
+from testutils import build_response, get_mock_jwt_auth
 from vonage_http_client.http_client import HttpClient
 from vonage_voice import (
     AudioStreamOptions,
@@ -18,8 +19,6 @@
 from vonage_voice.models.responses import CreateCallResponse
 from vonage_voice.voice import Voice
 
-from testutils import build_response, get_mock_jwt_auth
-
 path = abspath(__file__)