John Danielsen (born 13 July 1939) is a Danish former footballer who played as a midfielder. During his club career he played for Boldklubben 1909. He earned 27 caps for the Denmark national team, won a silver medal in football at the 1960 Summer Olympics, and was in the finals squad for the 1964 European Nations' Cup. He played for 1909 from Odense in Denmark. He was transferred to the German club Werder Bremen, later returning to play for B 1909 again at the end of his career in the early 1970s.