Surname Penjai (Penjai 
) , worldwide, is a very rare last name. The cognomen Penjai is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Much more prevalently, Penjai is the forename as well as the last name.
Jang, Boonsamram, Anantaphut, Sompongchaiyakul, Thitathan, Kaewsuwan, Jarenlap, Boriboon, Chaiwong, Mumaphai, Jiansuwan, Rodchum, Sopanna, Sinsamersuk, Utasoontorn, Inpean, Srinak, Meedach, Leelaburanapong, and Thongnuanjan