Sinjai Plengpanich, née Sinjai Hongtai, is a Thai actress who started her career as a model. She has acted in numerous lakorn as well as films and theatrical productions. In 2007, she starred in the critically acclaimed The Love of Siam, and also acted in a revival of the stage production, Banlangmek: The Musical. In 2013 remake of Khu Kam, Sinjai portrayed Thanphuying La-iat Phibunsongkhram, wife of Field Marshal Plaek Phibunsongkhram, former Prime Minister and military dictator.