The Roman Catholic Diocese of Tolagnaro (Latin: Tolagnaren(sis)) is a Latin suffragan diocese in the ecclesiastical province of Fort-Dauphin in Madagascar.
It depends on the missionary Roman Congregation for the Evangelization of Peoples.
Its cathedral episcopal seat is in Fort-Dauphin (Madagascar).
As of 2014 it served 128,000 Catholics (11.4% of 1,120,000 total) on 45,000 km2 in 16 parishes and 2 missions with 37 priests (17 diocesan, 20 religious), 134 lay religious (36 brothers, 98 sisters) and 15 seminarians.