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 1904, he was elected as a Liberal candidate to the House of Commons of Canada representing the riding of Saskatchewan (Provisional District), Northwest Territories.

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.

On April 2, 1927, he was appointed to the Supreme Court of Canada.