James Robertson Nowlin (born 1937) is a United States federal judge.
Born in San Antonio, Texas, Nowlin received a B.A. from Trinity University in 1959, an M.A. from Trinity University in 1962, and a J.D. from the University of Texas School of Law in 1963. He was in the United States Army Captain from 1959 to 1960. He was in the United States Army Reserve, JAG Corps from 1960 to 1968. He was in private practice in San Antonio, Texas from 1963 to 1965. He was a Legal counsel, U.S. Senate Committee on Labor and Public Welfare, Washington, DC from 1965 to 1966. He was a Member, Texas House of Representatives from 1967 to 1971 and from 1973 to 1981. He was in private practice in San Antonio, Texas from 1966 to 1981.
Nowlin was a federal judge on the United States District Court for the Western District of Texas. Nowlin was nominated by President Ronald Reagan on September 17, 1981, to a seat vacated by Jack Roberts. He was confirmed by the United States Senate on October 21, 1981, and received his commission on October 26, 1981. He served as chief judge from 1999-2003. He assumed senior status on May 31, 2003.