Tachileik is a border town in Shan State of eastern Myanmar. It is the administrative seat of Tachileik Township and Tachileik District and most populated city in eastern Shan State with 51,553 residents per 2014 census count, ahead of Kyaing Tong, but only 4th statewide. It faces Mae Sai in Thailand, and is home to one of Myanmar's seven official border trade posts with Thailand.