| Hemvadi | |
| Full Name: | Mandhana Bhavadi: (1892–1899) Hemvadi: (1899–1972) |
| House: | Chakri dynasty |
| Mother: | Hem Amatayakul |
| Birth Date: | 12 January 1892 |
| Birth Place: | Grand Palace Bangkok, Siam |
| Death Place: | Bangkok, Thailand |
Hemvadi (th|เหมวดี; ; 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 The Noble Consort (Chao Chom Manda) Hem Amatayakul (daughter of Lord (Phraya) Dhammasarnniti Vichitbakdi). After she was born, she was given the name from her father as Mandhana Bhavadi (th|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.
| Princess Hemvadi | Father: Chulalongkorn, King Rama V of Siam | Paternal Grandfather: Mongkut, King Rama IV of Siam | Paternal Great-grandfather: Buddha Loetla Nabhalai, King Rama II of Siam |
| Paternal Great-grandmother: Queen Sri Suriyendra | |||
| Paternal Grandmother: Queen Debsirindra | Paternal Great-grandfather: Prince Sirivongse, the Prince Matayabidaksa | ||
| Paternal Great-grandmother: Mom Noi Sirivongs na Ayudhya | |||
| Mother: Chao Chom Manda Ham Amatayakul | Maternal Grandfather: Lord (Phraya) Dhammasarnniti Vichitbakdi | Maternal Great-grandfather: unknown | |
| Maternal Great-grandmother: unknown | |||
| Maternal Grandmother: Saeng Amatayakul | Maternal Great-grandfather: unknown | ||
| Maternal Great-grandmother: unknown |