Mamasa Regency (Indonesian: Kabupaten Mamasa) is one of the six regencies that make up the West Sulawesi Province, Indonesia, on the island of Sulawesi.

Mamasa Regency is located at an altitude of 600-2,000 metres above sea level.

[6] The total population of this regency in 2020 was 163,383 people, of which men were 83,928 and women were 79,455;[3] the official estimate as at mid 2023 was 170,354.

Mamasa Regency has a diversity of ethnicities, religions, races and customs (SARA).

Mamasa has a tropical rainforest climate (Af) that closely borders a subtropical highland climate (Cfb) with moderate rainfall in August and September and heavy rainfall in the remaining months.