diff --git a/api/models/account.py b/api/models/account.py
index f993bc1523..567a2ceb94 100644
--- a/api/models/account.py
+++ b/api/models/account.py
@@ -92,7 +92,7 @@ class Account(UserMixin, Base):
     password_salt: Mapped[Optional[str]] = mapped_column(db.String(255))
     avatar: Mapped[Optional[str]] = mapped_column(db.String(255), nullable=True)
     interface_language: Mapped[str] = mapped_column(db.String(255))
-    interface_theme: Mapped[str] = mapped_column(db.String(255))
+    interface_theme: Mapped[Optional[str]] = mapped_column(db.String(255), nullable=True)
     timezone: Mapped[str] = mapped_column(db.String(255))
     last_login_at: Mapped[datetime] = mapped_column(db.DateTime)
     last_login_ip: Mapped[str] = mapped_column(db.String(255))