Saovabha Phongsri (Thai: เสาวภาผ่องศรี; RTGS: Saowapha Phongsi (Pronunciation)) was an agnatic half-sister, royal wife and queen consort of King Chulalongkorn (Rama V) of Thailand, and mother of both King Vajiravudh (Rama VI) and King Prajadhipok (Rama VII).

As in accordance with Thai royal tradition, King Vajiravudh later bestowed on his mother the title of "Queen Mother Sri Bajrindra" (Thai: ศรีพัชรินทร; RTGS: Si Phatcharin).

She gave him 9 children, 5 would survive to adulthood (one died in infancy), two would eventually become King of Siam.

In 1897, Queen Saovabha became the first female Regent of Siam, when her husband went on a tour of Europe.

When he returned he bestowed upon her the title of "Somdet Phra Nang Chao Saowapha Phongsi Praborommarachininat" (RTGS) (Thai: สมเด็จพระนางเจ้าเสาวภาผ่องศรี พระบรมราชินีนาถ) (roughly equivalent to H.M. the Queen Regent).