John Theophilus Jenkins (October 12, 1829 – January 17, 1919) was a physician and political figure in Prince Edward Island.
He represented Charlottetown in the Legislative Assembly of Prince Edward Island from 1873 to 1876 and Queen's County in the House of Commons of Canada from 1882 to 1883 and from 1884 to 1887 as a Liberal-Conservative member.
He was educated at the Central Academy in Charlottetown and at St Bartholomew's Hospital in London, England.
He was coroner and health officer for Charlottetown and married Jessie Esther, the daughter of Stephen Rice in 1856.
He was elected to the provincial assembly in 5th Queens in an 1891 by-election held after Patrick Blake ran unsuccessfully for a seat in the House of Commons and served until 1893.