Princess Puangsoi Sa-ang (; 30 September 1866 â 23 April 1950) was a member of Siamese royal family. She was a daughter of King Mongkut and Concubine Tieng Rojadis and half-sister of Chulalongkorn.
Her mother was Chao Chom Manda Tieng Rojanadis (daughter of Phraya Abbhantrikamat and Klai Rojanadis). She was given full name as Phra Chao Borom Wong Ther Phra Ong Chao Phuangsoi Sa-ang ().