Sang Sinxay (Lao: ສັງສິນໄຊ, also known as Sinxay or Sinsai), is a Lao epic poem written by Pang Kham. It tells the story of the hero Sinxay (ສິນໄຊ) who goes on a quest to rescue his aunt Soumountha (ສູມຸນທາ) who was abducted by the demon Nyak Koumphan (ຍັກກູມພັນ). The poem is believed to have been written sometime between the mid-16th and the end of the 17th century in the Lao kingdom of Lan Xang. Sang Sinxay is considered one of the three masterpieces of Lao literature.