Marlin Keith Jensen (born May 18, 1942) is an American attorney who has been a general authority of the Church of Jesus Christ of Latter-day Saints (LDS Church) since 1989. He served as the official Church Historian and Recorder of the church from 2005 to 2012. He was the 19th man to hold that calling since it was established in 1830. Jensen was made an emeritus general authority in the October 2012 general conference.

Jensen was born in Huntsville, Utah. As a 19-year-old, he served as a missionary for the LDS Church in West Germany. After returning home in 1964, he earned a Bachelor of Science degree in German from Brigham Young University. He earned a Juris Doctor from the University of Utah College of Law in 1970, graduating first in his class.

At the age of 28, he served as bishop of his ward in Huntsville, as had both his father and grandfather. He later served as president of the Huntsville Utah Stake. In 1987 he became a regional representative for the Kaysville Utah and Layton Utah regions.

Professionally, Jensen was an attorney in private practice in Ogden, Utah, specializing in business and estate planning. This supported his real passion of living a farming lifestyle. His family operates a ranching enterprise called Jensens' Middle Fork Ranch, in which he is a partner.

In August 2012, Utah Governor Gary Herbert nominated Jensen to serve on the Utah State Board of Regents, which oversees the state's colleges and universities.

In 1989, Jensen became a member of the First Quorum of the Seventy at the age of 46. In 1993, he was made assistant executive director of the church's Priesthood Department, later becoming executive director until 2001. From 1993 to 1995, while a general authority, Jensen served as president of the church's New York Rochester Mission. In 1995, Jensen became a member of the church's Public Affairs Committee. From 1996 to 1998 he was executive director of the Church Historical Department. He served in the First Quorum of the Seventy until 1998, when he became a member of the Presidency of the Seventy, and in 2000 he also became the general president of the church's Sunday School. Jensen served in these positions until 2001. In 2004, he replaced D. Todd Christofferson as executive director of the Family and Church History Department, a position he held previously when it was just the Historical Department. In 2005, he became the first Church Historian and Recorder to serve since 1997. He served in this capacity until 2012 and was designated an emeritus general authority in October 2012.

Jensen is one of the few general authorities of the LDS Church who self-identifies as a member of the Democratic Party.

Jensen has served in various area presidency positions. As a new Seventy in 1989, he was counselor to John K. Carmack, president of the Utah Central Area. From 1990 to 1992, Jensen served as president of the Utah North Area. He later served first as a counselor, then as president, of the North America Northeast Area. He was president of the Europe Central Area from 2001 to 2003.