Kapai, officially the Municipality of Kapai, is a municipality in the province of Lanao del Sur, Philippines. According to the 2020 census, it has a …Kapai, officially the Municipality of Kapai, is a municipality in the province of Lanao del Sur, Philippines. According to the 2020 census, it has a population of 20,581 people. Kapai is politically subdivided into 20 barangays. Each barangay consists of puroks while some have sitios.