Sir Joseph Fayrer, Baronet (6 December 1824 - 21 May 1907) was an English physician noted for his writings on medicine in India.

He was born at Plymouth. After studying medicine at Charing Cross Hospital , London, he was in 1847 appointed medical officer of HMS Victory, and soon afterwards accompanied Ernest Augustus Edgcumbe, 3rd Earl of Mount Edgcumbe on a tour through Europe, in the course of which he saw fighting at Palmero and Rome.

Appointed an assistant surgeon in Bengal in 1850, he went through the Burmese campaign of 1852 and was political assistant and Residency surgeon at Lucknow during the Indian Mutiny. From 1859 to 1872 he was professor of surgery at the Medical College of Calcutta , and when the prince of Wales made his tour in India he was appointed to accompany him as physician. Returning from India, he acted as president of the Medical Board of the India office from 1874 to 1895, and in 1896 he was created a baronet.

Fayrer, who became a fellow of the Royal Society in 1877, wrote much on subjects connected with the practice of medicine in India, and was especially known for his studies on the poisonous snakes of that country and on the physiological effects produced by their virus (Thanatophidia of India, 1872). In 1900 appeared his Recollections of my Life. He died at Falmouth in 1907.