An amphoe (Thai: อำเภอ, romanized: amphơ̄, IPA: [ʔāmpʰɤ̄ː]; 'district'), also anglicised as amphur ( or ), is the second level administrative subdivision of Thailand. Groups of amphoe or districts make up the provinces, and are analogous to counties. The chief district officer is Nai Amphoe (นายอำเภอ). Amphoe are divided into tambons (Thai: ตำบล; 'subdistricts').
Altogether Thailand has 928 districts, including the 50 districts of Bangkok, which are called khet (เขต) since the Bangkok administrative reform of 1972. The number of districts in provinces varies, from only three in the smallest provinces, up to the 50 urban districts of Bangkok. Also the sizes and population of districts differ greatly. The smallest population is in Ko Kut (Trat province) with just 2,042 citizens, while Mueang Samut Prakan (Samut Prakan province) has 509,262 citizens. The khet of Bangkok have the smallest areas—Khet Samphanthawong is the smallest, with only 1.4 km—while the amphoe of the sparsely populated mountain regions are bigger than some provinces. Umphang (Tak province) at 4,325.4 km is the largest and also has the lowest population density. The average area of a district in Thailand is about 552.93 km (213.49 sq mi), while its average population of a district in Thailand is about 75,345 people.