The incident occurred at Adharmanik village under Dholahat police station in in South 24 Parganas district where the class IX student was having an affair with the boy.
Her father Mansoor Ali Lashkar had warned her not to continue any relation with him but she did not pay heed to it.
Angry with her disobedience, Lashkar tried to strangulate his daughter, hit her with a stick on the head and slashed her tongue with a sharp weapon last night, the police said.
She was found in the morning by villagers and was admitted to the Sadar Hospital at Diamond Harbour in a serious condition.
Lashkar and his two aides were at large, the police said.