The Happiest Day in the Life of Olli Mäki is a 2016 biographical drama film directed by Juho Kuosmanen and written by Mikko Myllylahti and Kuosmanen. An international co-production between Finland, Sweden, and Germany, the film stars Jarkko Lahti, Oona Airola, and Eero Milonoff. It tells the true story of Olli Mäki, the famous Finnish boxer who had a shot at the 1962 World Featherweight title.