Claude Gilbert "Mike" McCormack (December 14, 1921 – November 7, 2020) was an American politician, who served as U.S. Representative from the State of Washington's Fourth Congressional District from 1971 to 1981.

In 1956, at age 35, McCormack was first elected to a public office as member of the Washington State House of Representatives, and was re-elected in 1958.

McCormack entered the United States Congress in 1971 as the only Member with a degree in Science, emerging as an expert on energy matters, a prominent issue during the years of his congressional service.

McCormack was a cosponsor in a successful attempt to pass legislation intended to facilitate general conversion of the United States to the metric system of measurement.

In 1999, McCormack received the Charles Lathrop Parsons Award,[4] the purpose of which is: "To recognize outstanding public service by a member of the American Chemical Society."