John Garvan Murtha (born 1941) is a United States federal judge.
Born in Hartford, Connecticut, Murtha received a B.A. from Yale University in 1963, an LL.B. from the University of Connecticut School of Law in 1968, and an LL.M. from Georgetown University Law Center in 1970. He was an E. Barrett Prettyman fellow at the Georgetown University Law Center from 1968 to 1970, and then became a deputy state's attorney of Windham County, Vermont from 1970 to 1973. He was in private practice in Brattleboro, Vermont from 1973 to 1995.
On April 4, 1995, President Bill Clinton nominated Murtha to a seat on the United States District Court for the District of Vermont vacated by Franklin S. Billings, Jr.. Murtha was confirmed by the United States Senate on May 25, 1995, and received his commission on May 26, 1995. He served as chief judge, 1995-2002.