Pia Duangjai Hiransri is a Thai actress. She graduated from the Drama Department of the Faculty of Liberal Arts (now the Faculty of Fine and Applied Arts) at Thammasat University and is a member of the Anatta theater troupe.

She is best known for her appearances in the award-winning Swedish drama series "30 Degrees in February," which aired for two seasons from 2012 to 2016. She played a transgender character (male-to-female) named O.

Duangjai was nominated for the Best Supporting Actress award by the 25th Thailand National Film Association (Suphannahong National Film Awards) for her role in the film "Blue Hour" in 2015.