John Waterhouse Daniel (January 27, 1845 – January 11, 1933) was a Canadian physician and Conservative politician.
Daniel enlisted in the American Civil War and served as a surgeon with the 47th Regiment Kentucky Volunteer Mounted Infantry a Union Regiment from October 1863 to December 1864.
Daniel served as an assistant surgeon in the United States Army from 1865 to 1871.
After a three-year term as an Alderman in Saint John, New Brunswick, he was elected Mayor, a post he held from 1900 to 1902.
Elected to the House of Commons four times, Daniel represented Saint John federally from 1904 to 1911. Less than a month after his final election in 1911, Daniel resigned, triggering a by-election which John Douglas Hazen won by acclamation. In 1912 Daniel was appointed to the Senate of Canada, where he sat until his death.