Hemvadi (Thai: เหมวดี; RTGS: Hemwadi; 12 January 1892 – 17 October 1972), was the Princess of Siam (later Thailand). She was a member of Siamese Royal Family. She is a daughter of Chulalongkorn, King Rama V of Siam. Her mother was (daughter of ). After she was born, she was given the name from her father as Mandhana Bhavadi (Thai: มัณฑนาภาวดี). Later her father changed her name shorter into Hemvadi, on 8 January 1899, while she was 6 years old. She lived in the Grand Palace all the rest of her life, and died on 17 October 1972, at the age of 80.