Thạnh Phú is a rural district of Bến Tre province in the Mekong Delta region of Vietnam. As of 2019 the district had a population of 127,841. The district covers an area of 401 km². The district capital lies at Thạnh Phú. The district is in the southeast of the province. To the north is the Hàm Luông River and Ba Tri district, to the south is the Chiên River and Trà Vinh province, to the west is Mỏ Cày district and to the east is the South China Sea.