John Thomas Marten (born 1951) is a United States federal judge.
Born in Topeka, Kansas, Marten received a B.A. from Washburn University in 1973 and a J.D. from Washburn University School of Law in 1976. He was a law clerk to Justice Tom C. Clark of the Supreme Court of the United States from 1976 to 1977. He was in private practice in Omaha, Nebraska from 1977 to 1980, then in Minneapolis, Minnesota until 1981, and then in McPherson, Kansas until 1996.
On October 18, 1995, Marten was nominated by President Bill Clinton to a seat on the United States District Court for the District of Kansas vacated by Patrick F. Kelly. Marten was confirmed by the United States Senate on January 2, 1996, and received his commission on January 4, 1996.