Albert Sydney Ashmead, Jr (1850-1911) was an American leprologist, one of the founders of the International Leprosy Congress.

He was born in Philadelphia on 4 April 1850. His parents were Albert Sydney Ashmead, a merchant, and Elizabeth Graham. After receiving his primary education at the Hastings Academy in West Philadelphia, Ashmead received his MD from the University of Pennsylvania in 1869. He then took an auxiliary medical course at the University as well as a postgraduate course at Jefferson Medical College. From 1871 to 1873 Ashmead practised medicine in Philadelphia.

In 1873 he was called to Washington to attend Prince Adzumo, brother of the Emperor of Japan. He was subsequently appointed Foreign Medical Director of the Tokyo Fu Hospital in Japan and taught the first class of students at the medical school of the Tokyo Charity Hospital. Ashmead returned to the United States in 1876. He then practised medicine in Doniphan County, Kansas, and was the first assistant surgeon for the St. Joseph and Denver City Railroad, and examining surgeon for the US Pension Bureau. In 1882, Ashmead moved to New York City to practice medicine.

In New York, Ashmead pursued his primary medical interest the study of leprosy. He was a motivating force behind the formation of the first International Leprosy Congress, held in Berlin in 1897; representatives of twenty two governments were present. A policy to impose absolute isolation of all those with the disease was proposed but defeated during the course of the conference. Ashmead was a firm believer in the contagiousness of leprosy and was the author of the Platt leper bill which came before the U.S.Senate on 22 January 1902. The bill advocated the appointment of a national commissioner of leprosy, the foundation of a national leper home, funding for leprosaria throughout the country, strict isolation of all those with leprosy in America, and a ban on emigration of anyone with the disease into the country.

In addition to his work on leprosy, Ashmead carried out research on syphilis, insanity, pellagra, and Asiatic diseases such as beriberi. He was a keen anthropologist, and was particularly interested in the origins of diseases: in the 1890s, he became involved in a scholarly dispute with Rudolf Virchow over leprosy in pre-Columbian Peru.

He was a member of the University of Pennsylvania medical club, a corresponding member of the Berlin anthropological society, and a member of the Medical Society of Japan.

Albert S Ashmead died in Philadelphia on 20 February 1911 after an intestinal operation.