Mamasapano is a municipality in the province of Maguindanao.

According to the 2000 census, it has a population of 20,059 people in 2,964 households.

Mamasapano is politically subdivided into 18 barangays.

Characterized by a more or less even distribution of rainfall throughout the year, the coldest months in the province are December and January. The warm season is from March to June.