diff --git a/api/tasks/delete_account_task.py b/api/tasks/delete_account_task.py
index fb5eb1d691..cb703cc263 100644
--- a/api/tasks/delete_account_task.py
+++ b/api/tasks/delete_account_task.py
@@ -2,6 +2,7 @@ import logging
 
 from celery import shared_task
 
+from configs import dify_config
 from extensions.ext_database import db
 from models import Account
 from services.billing_service import BillingService
@@ -14,7 +15,8 @@ logger = logging.getLogger(__name__)
 def delete_account_task(account_id):
     account = db.session.query(Account).where(Account.id == account_id).first()
     try:
-        BillingService.delete_account(account_id)
+        if dify_config.BILLING_ENABLED:
+            BillingService.delete_account(account_id)
     except Exception:
         logger.exception("Failed to delete account %s from billing service.", account_id)
         raise
diff --git a/api/tests/unit_tests/tasks/test_delete_account_task.py b/api/tests/unit_tests/tasks/test_delete_account_task.py
new file mode 100644
index 0000000000..3b148e63f2
--- /dev/null
+++ b/api/tests/unit_tests/tasks/test_delete_account_task.py
@@ -0,0 +1,112 @@
+"""
+Unit tests for delete_account_task.
+
+Covers:
+- Billing enabled with existing account: calls billing and sends success email
+- Billing disabled with existing account: skips billing, sends success email
+- Account not found: still calls billing when enabled, does not send email
+- Billing deletion raises: logs and re-raises, no email
+"""
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from tasks.delete_account_task import delete_account_task
+
+
+@pytest.fixture
+def mock_db_session():
+    """Mock the db.session used in delete_account_task."""
+    with patch("tasks.delete_account_task.db.session") as mock_session:
+        mock_query = MagicMock()
+        mock_session.query.return_value = mock_query
+        mock_query.where.return_value = mock_query
+        yield mock_session
+
+
+@pytest.fixture
+def mock_deps():
+    """Patch external dependencies: BillingService and send_deletion_success_task."""
+    with (
+        patch("tasks.delete_account_task.BillingService") as mock_billing,
+        patch("tasks.delete_account_task.send_deletion_success_task") as mock_mail_task,
+    ):
+        # ensure .delay exists on the mail task
+        mock_mail_task.delay = MagicMock()
+        yield {
+            "billing": mock_billing,
+            "mail_task": mock_mail_task,
+        }
+
+
+def _set_account_found(mock_db_session, email: str = "user@example.com"):
+    account = SimpleNamespace(email=email)
+    mock_db_session.query.return_value.where.return_value.first.return_value = account
+    return account
+
+
+def _set_account_missing(mock_db_session):
+    mock_db_session.query.return_value.where.return_value.first.return_value = None
+
+
+class TestDeleteAccountTask:
+    def test_billing_enabled_account_exists_calls_billing_and_sends_email(self, mock_db_session, mock_deps):
+        # Arrange
+        account_id = "acc-123"
+        account = _set_account_found(mock_db_session, email="a@b.com")
+
+        # Enable billing
+        with patch("tasks.delete_account_task.dify_config.BILLING_ENABLED", True):
+            # Act
+            delete_account_task(account_id)
+
+        # Assert
+        mock_deps["billing"].delete_account.assert_called_once_with(account_id)
+        mock_deps["mail_task"].delay.assert_called_once_with(account.email)
+
+    def test_billing_disabled_account_exists_sends_email_only(self, mock_db_session, mock_deps):
+        # Arrange
+        account_id = "acc-456"
+        account = _set_account_found(mock_db_session, email="x@y.com")
+
+        # Disable billing
+        with patch("tasks.delete_account_task.dify_config.BILLING_ENABLED", False):
+            # Act
+            delete_account_task(account_id)
+
+        # Assert
+        mock_deps["billing"].delete_account.assert_not_called()
+        mock_deps["mail_task"].delay.assert_called_once_with(account.email)
+
+    def test_account_not_found_billing_enabled_calls_billing_no_email(self, mock_db_session, mock_deps, caplog):
+        # Arrange
+        account_id = "missing-id"
+        _set_account_missing(mock_db_session)
+
+        # Enable billing
+        with patch("tasks.delete_account_task.dify_config.BILLING_ENABLED", True):
+            # Act
+            delete_account_task(account_id)
+
+        # Assert
+        mock_deps["billing"].delete_account.assert_called_once_with(account_id)
+        mock_deps["mail_task"].delay.assert_not_called()
+        # Optional: verify log contains not found message
+        assert any("not found" in rec.getMessage().lower() for rec in caplog.records)
+
+    def test_billing_delete_raises_propagates_and_no_email(self, mock_db_session, mock_deps):
+        # Arrange
+        account_id = "acc-err"
+        _set_account_found(mock_db_session, email="err@ex.com")
+        mock_deps["billing"].delete_account.side_effect = RuntimeError("billing down")
+
+        # Enable billing
+        with patch("tasks.delete_account_task.dify_config.BILLING_ENABLED", True):
+            # Act & Assert
+            with pytest.raises(RuntimeError):
+                delete_account_task(account_id)
+
+        # Ensure email was not sent
+        mock_deps["mail_task"].delay.assert_not_called()