Willis Merwyn (Merv) Johnson (born May 9, 1923) is a Saskatchewan farmer and former politician.
Johnson was the Co-operative Commonwealth Federation Member for Parliament for Kindersley, Saskatchewan. He first won his seat in the Canadian House of Commons in the 1953 federal election and was re-elected in 1957 before being defeated in the 1958 general election in the Diefenbaker landslide. He attempted to re-enter the House of Commons in several subsequent elections as a New Democrat but was unsuccessful.
In 1977, Johnson was appointed to serve as Saskatchewan's agent-general in London, England. He also served for several years as president of the Saskatchewan CCF-NDP and was president of the federal New Democratic Party of Canada from 1963 to 1965.