J. Marinus Jensen (1868-1946) was a professor of English and journalism in Utah.

James Marinus Jensen, at times identified as Jens Marinus Jensen, was born on July 11, 1868 in Provo, Utah to Danish emigrants Peter C. Jensen and Ane Catherine Olson. He was raised in Provo, and grew to be active in the city's religious, civic, and political life. As a young man he participated in the Provo Dramatic Club, traveling widely with the troupe. On September 22, 1892 he married Eliza Emeline Strong (1867-1934) in the Manti Temple. They had no children of their own, but helped raise Essie R. Keeler as foster parents.

Jensen worked as a teacher in Provo throughout his career. He attended the University of Utah and Brigham Young Academy, graduating from the latter in 1903 with a bachelor's of pedagogy. He served as a the first principal of Maeser Elementary School, and also served at Franklin Elementary. He continued his education at the University of Chicago, earning a master's degree in 1919. He then began working in the English Department at Brigham Young University, where he helped found the school's journalism program. In addition to his work at the university, Jensen was also a reporter for the Provo Inquirer.

During his time at Brigham Young University, Jensen served in many committee assignments. Among these was an assignment to chair the History Committee, where he prepared histories of Provo and of the university. He also served in the community on the city council, the public library board, and as the bishop of the Manavu Ward.

Jensen died in Provo, Utah on March 16, 1946.