Marius Halvor Skram-Jensen aka John Jensen (1 March 1881 in Slagelse, Denmark – 17 January 1975 in Harriman, Tennessee, USA) was a Danish gymnast who competed in the 1906 Summer Olympics.
In 1906, he won the silver medal as a member of the Danish gymnastics team in the team competition.
In 1910 he emigrated to the United States, and changed his name to John Jensen.