The woman died at Karachi's Civil Hospital of burn injuries sustained during the incident last month in Daharki town in southern Sindh province.
The woman, whose daughter was raped and burned alive by three men, alleged that she too was raped.
The three men who the woman had named in her statement to a magistrate are still at large.
A relative of the victims expressed dissatisfaction over the her treatment, accusing the doctors of not providing her proper care in the hospital.