diff --git a/redash/destinations/webhook.py b/redash/destinations/webhook.py
index b98b6f18a3..d8169bbb65 100644
--- a/redash/destinations/webhook.py
+++ b/redash/destinations/webhook.py
@@ -42,7 +42,7 @@ def notify(self, alert, query, user, new_state, app, host, metadata, options):
             auth = HTTPBasicAuth(options.get("username"), options.get("password")) if options.get("username") else None
             resp = requests.post(
                 options.get("url"),
-                data=json_dumps(data),
+                data=json_dumps(data).encode("utf-8"),
                 auth=auth,
                 headers=headers,
                 timeout=5.0,
diff --git a/tests/handlers/test_destinations.py b/tests/handlers/test_destinations.py
index 00a52cbb00..6ac410020b 100644
--- a/tests/handlers/test_destinations.py
+++ b/tests/handlers/test_destinations.py
@@ -7,6 +7,7 @@
 from redash.destinations.discord import Discord
 from redash.destinations.slack import Slack
 from redash.destinations.webex import Webex
+from redash.destinations.webhook import Webhook
 from redash.models import Alert, NotificationDestination
 from tests import BaseTestCase
 
@@ -518,3 +519,48 @@ def test_datadog_notify_calls_requests_post():
         )
 
         assert mock_response.status_code == 202
+
+
+def test_webhook_notify_handles_unicode():
+    # Create a mock alert with all the properties needed by serialize_alert
+    alert = mock.Mock()
+    alert.id = 1
+    alert.name = "Test Alert"
+    alert.custom_subject = "Test Subject With Unicode: 晨"
+    alert.custom_body = "Test Body"
+    alert.options = {}
+    alert.state = "ok"
+    alert.last_triggered_at = None
+    alert.updated_at = "2025-12-02T08:00:00Z"
+    alert.created_at = "2025-12-02T08:00:00Z"
+    alert.rearm = None
+    alert.query_id = 10
+    alert.user_id = 20
+
+    query = mock.Mock()
+    user = mock.Mock()
+    app = mock.Mock()
+    host = "http://redash.local"
+    options = {"url": "https://example.com/webhook", "username": "user", "password": "password"}
+    metadata = {}
+    new_state = Alert.TRIGGERED_STATE
+    destination = Webhook(options)
+
+    with mock.patch("redash.destinations.webhook.requests.post") as mock_post:
+        mock_response = mock.Mock()
+        mock_response.status_code = 200
+        mock_post.return_value = mock_response
+
+        destination.notify(alert, query, user, new_state, app, host, metadata, options)
+
+        # Get the data passed to the mock
+        call_args, call_kwargs = mock_post.call_args
+        sent_data = call_kwargs["data"]
+
+        # 1. Make sure we send bytes
+        assert isinstance(sent_data, bytes)
+
+        # 2. Make sure the bytes are the correct UTF-8 encoded JSON
+        decoded_data = json.loads(sent_data.decode("utf-8"))
+        assert decoded_data["alert"]["title"] == alert.custom_subject
+        assert "Test Subject With Unicode: 晨" in sent_data.decode("utf-8")