John Peavey (born September 1, 1933) is a rancher and Democratic politician from Carey, Idaho. Peavey served in the Idaho Senate from 1969 to 1976 and from 1978 to 1994.
From a young age Peavey worked on the ranch founded by his grandfather, U.S. Senator John W. Thomas. In 1969 he succeeded his mother, Mary Brooks in the Idaho Senate as a Republican after she was appointed director of the United States Mint by President Richard M. Nixon.
In 1974, after repeated attempts to pass a Sunshine Law; a law requiring lobbyists to register and political campaign disclosure, in the legislature were unsuccessful, Peavey led a successful state wide campaign to pass one by ballot initiative. The passage of the act angered state GOP party officials who recruited a Rupert farmer to run against him in the 1976 Republican primary. When the opponent won, Peavey switched parties and ran as a Democrat in 1978 and won back his seat. In the early and mid-1990s he served as the Idaho Senate Minority Caucus Chairman. As a state senator, Peavey was noted for rarely appearing in public without wearing a cowboy hat.
In 1994 Peavey was the Democratic nominee for lieutenant governor. He was defeated by the Republican incumbent Butch Otter, who was later elected governor in 2006.