Suddha Dibyaratana, Princess of Rattanakosin (Thai: สุทธาทิพยรัตน์; RTGS: Sutthathipphayarat; 14 September 1877 – 2 January 1922), was the Princess of Siam (later Thailand). She was a member of the Siamese Royal Family. She was given the highest rank of any daughter of Chulalongkorn, King Rama V of Siam. On 9 August 1906, she was given the royal title of The Princess of Rattanakosin, translated in Thai as Krommaluang Si Rattanakosin (Thai: กรมหลวงศรีรัตนโกสินทร). She was the only daughter given the rank of Krommaluang, the 3rd level of the Krom ranks.