Harvey Cathcart Simpson (February 11, 1862—January 29, 1928) was a politician in Manitoba, Canada. He served in the Legislative Assembly of Manitoba from 1909 to 1914, as a member of the Conservative Party. Simpson was born in Ashton, Canada West (now Ontario), and educated at Ashton and Carleton Place. He came west in 1882, settling in Virden, Manitoba. In religion, Simpson was a Methodist. In 1882, he married Rhodella Armstrong Irwin. Simpson lost to Liberal George Clingan by 85 votes in the 1914 election. He served overseas as a captain during World War I.