Prince Isariyabhorn or Phra Chao Boromwongse Ther Phra Ong Chao Isariyabhorn (RTGS: Isariyaphorn) (Thai: พระเจ้าบรมวงศ์เธอ พระองค์เจ้าอิศริยาภรณ์) (21 October 1888 – 21 September 1892), was a Prince of Siam (later Thailand).
He was a member of the Siamese royal family.
He was a son of Chulalongkorn, King Rama V of Siam.
He had a younger brother, Prince Anusara Siriprasadh.
Prince Isariyabhorn died at the age of 3 years and 11 months on 21 September 1892.