Ole Colbjørnsen (30 May 1897, Vegårshei, Aust-Agder – 12 November 1973) was a Norwegian journalist, economist and politician for the Labour Party.
He was born in Vegårshei as a son of Torjus Taxeraas (1859–1918) and Marie Colbjørnsen (1869–1958). He took his examen artium in Arendal before turning 18 years old, and enrolled as a student in 1915. He studies natural sciences, and got work as an assistant of professors Carl Størmer and Lars Vegard. He also joined the Norwegian Labour Party while studying, and became involved in politics. He identified as a communist, and became interested in working for the Soviet Union. From 1921 he worked in the state news agency Russian Telegraph Agency (ROSTA), and from 1922 to 1928 he worked with trade and finance for the Soviet Union. Eventually he worked with organizing and preparing the First Five-Year Plan. From 1929 to 1931 he headed a shipping company based in London, working with Soviet timber exports.
In 1931 he returned to Norway. He worked as a financial journalist in the Labour Party's newspaper Arbeiderbladet from the autumn of 1932. The chief editor of Arbeiderbladet, Martin Tranmæl, was also a prominent party member. As Colbjørnsen broadcast new economic ideas through his articles, among others inspired by John Maynard Keynes and William Beveridge, he too became more involved in the Labour Party. He was invited to the Labour Party national convention of 1933, where he showcased a number of reform proposals. In the same year he wrote the pamphlet Hele folket i arbeid, which also became the party slogan. In 1934 he issued the document En norsk treårsplan together with Axel Sømme. In it, the authors laid out reforms for a three-year economic plan. Colbjørnsen has been called "Norway's first plan economist". The Labour Party had tried a radical and revolutionary tactic ahead of the 1930 general election, but suffered a defeat there. Historians generally agree that from this point, the Labour Party decisively drifted away from the revolutionary rhetoric and policies. Colbjørnsen and Sømme helped build a new political platform. First, they helped shift the labour movement's focus from redistribution to production. Second, they helped create acceptance for doing this within the framework of the state, earlier lambasted as bourgeois.