Irving Moffat Cleghorn (August 22, 1863^[1] – November 14, 1929^[2]) was a politician in Manitoba, Canada. He served in the Legislative Assembly of Manitoba from 1927 to 1929, as a member of the Manitoba Liberal Party.^[3]

Born in Moffat, Scotland, Cleghorn came to Canada with his family at the age of four. They settled in Wingham, Ontario. He studied medicine at the Manitoba Medical College^[1] and set up practice in Belmont, Manitoba in 1891, moving to Baldur the following year. Cleghorn also operated a pharmacy in Baldur from 1903 until 1929.^[4] He was elected to the Manitoba legislature in the 1927 provincial election, defeating Progressive incumbent Charles Cannon^[3] by 84 votes.

The election was won by the Progressive Party. Cleghorn served on the opposition benches for the next two years^[3] and died at home in Baldur while still a member of the legislature.^[2]