Kyainseikgyi Township (Phlone: ; , ) is the only township of Kyain Seikkyi District () in southern Kayin State of Myanmar. It is the fourth-biggest township in Kayin State. The two main sub-towns are Kyeikdon and Payathonsu. It is drained by the Zami, Winyaw and the Haungtharaw rivers.
The basic education high schools located within Kyain Seikgyi Township are BEHS Kyainnseikyi, B.E.H.S-Tagondaing, BEHS Kale, BEHS Hparpya, BEHS Anankwin, BEHS Kyaikdon, BEHS Azin, BEHS Kyakhatchaung, BEHS Thanpayar, BEHS Taungpauk and BEHS Payathonzu. The main hospitals are Kya Inn Seikyi township public hospital, Kale-Tagundaing Station Hospital, Kyaikdon Station hospital, Payathonzu Station Hospital.
The township contains the following subtownships: