Vu Thi Deu, 61, died at the National Institute of Burns in Hanoi after 40 days of treatment, her family said.
Two of her daughters, Do Thi Dinh, 40, and Do Thi Diem, 34, had died of burn injuries in November, and the youngest daughter, Do Thi Dua, 32, had the least severe injuries but remains in hospital.
The Hung Yen police said Deu and her three daughters had been quarreling over property inheritance, and on October 30 the daughters brought a can of gasoline to Deu's house in Yen My District and set it on fire.