John Henderson Lamont (November 12, 1865 – March 10, 1936) was a Canadian lawyer, politician, and Justice of the Supreme Court of Canada.

Born in Horning's Mills, Canada West (now Ontario), the son of Duncan Carmichael Lamont and Margaret Robson Henderson, he received a Bachelor of Arts degree in 1892 and a Bachelor of Law degree in 1893 from the University of Toronto. In 1893, he was called to the Bar of Ontario.

He practised law in Toronto until 1899 when he moved to Prince Albert, Northwest Territories (now Saskatchewan) and co-founded a law firm.

In 1902, he became a Crown Prosecutor. In 1904, he was elected as a Liberal candidate to the House of Commons of Canada representing the riding of Saskatchewan (Provisional District), Northwest Territories. In this election he defeated Conservative Thomas McKay who had been elected first mayor of Prince Albert in the 1880s. He resigned on September 5, 1905 and was elected as a Liberal to represent the district of Prince Albert City in the first election of the Legislative Assembly of Saskatchewan. He was also appointed Attorney General. In 1907, he was appointed to the Supreme Court of Saskatchewan. From 1918 to 1927, he was a Justice of the Saskatchewan Court of Appeal. On April 2, 1927, he was appointed to the Supreme Court of Canada. He served until his death in 1936.

Lamont, Alberta is named in his honour.

• Supreme Court of Canada biography
• John Henderson Lamont – Parliament of Canada biography