diff --git a/CHANGES/1233.bugfix.rst b/CHANGES/1233.bugfix.rst
new file mode 100644
index 00000000..17aa8fbc
--- /dev/null
+++ b/CHANGES/1233.bugfix.rst
@@ -0,0 +1,4 @@
+Added model validation to remove UNSET before field validation.
+This change was necessary to correctly handle parse_mode where 'UNSET' is used as a sentinel value.
+Without the removal of 'UNSET', it would create issues when passed to model initialization from Bot.method_name.
+'UNSET' was also added to typing.
diff --git a/aiogram/types/base.py b/aiogram/types/base.py
index 641b16df..9c24c703 100644
--- a/aiogram/types/base.py
+++ b/aiogram/types/base.py
@@ -1,7 +1,7 @@
-from typing import Any
+from typing import Any, Dict
 from unittest.mock import sentinel
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, model_validator
 
 from aiogram.client.context_controller import BotContextController
 
@@ -17,6 +17,19 @@ class TelegramObject(BotContextController, BaseModel):
         defer_build=True,
     )
 
+    @model_validator(mode="before")
+    @classmethod
+    def remove_unset(cls, values: Dict[str, Any]) -> Dict[str, Any]:
+        """
+        Remove UNSET before fields validation.
+
+        We use UNSET as a sentinel value for `parse_mode` and replace it to real value later.
+        It isn't a problem when it's just default value for a model field,
+        but UNSET might be passed to a model initialization from `Bot.method_name`,
+        so we must take care of it and remove it before fields validation.
+        """
+        return {k: v for k, v in values.items() if not isinstance(v, UNSET_TYPE)}
+
 
 class MutableTelegramObject(TelegramObject):
     model_config = ConfigDict(
@@ -24,7 +37,7 @@ class MutableTelegramObject(TelegramObject):
     )
 
 
-# special sentinel object which used in situation when None might be a useful value
+# special sentinel object which used in a situation when None might be a useful value
 UNSET: Any = sentinel.UNSET
 UNSET_PARSE_MODE: Any = sentinel.UNSET_PARSE_MODE
 UNSET_DISABLE_WEB_PAGE_PREVIEW: Any = sentinel.UNSET_DISABLE_WEB_PAGE_PREVIEW