John Decker Butzner Jr. (October 2, 1917 – January 20, 2006) was a United States federal judge.
Butzner was born in Scranton, Pennsylvania, and as a child, he began to become interested in the law when he visited his uncle Billy Butzner, a lawyer. His sister, Jane Jacobs, was a leading twentieth century urbanist and reformer. He did his undergraduate work at the University of Scranton, graduating magna cum laude in 1938, and went on to the University of Virginia School of Law. While there, he served on the board of editors of the Virginia Law Review. In 1941, Butzner received his LL.B. and started practicing law at his uncle's firm of Butzner & Hicks in Fredericksburg, Virginia, but his career was interrupted by World War II the following year. From 1942 to 1945, Butzner was a staff sergeant in the United States Army Air Forces Weather Service in Alaska. With the war's end, Butzner returned to private practice in Fredericksburg. Within two years, he married his wife, Viola Peterson.
Butzner's career in private practice ended in 1958, when he became an associate judge of Virginia's 15th Judicial Circuit. He stayed in that role until 1960, when he became a judge of Virginia's 39th Judicial Circuit.
Two years later, on May 15, 1962, President John F. Kennedy nominated him to a seat on the United States District Court for the Eastern District of Virginia vacated by Albert V. Bryan. He was confirmed by the United States Senate on June 15, 1962, and received his commission on June 20, 1962. Butzner was nominated by President Lyndon B. Johnson on June 27, 1967, to a seat on the United States Court of Appeals for the Fourth Circuit vacated by J. Spencer Bell. Butzner was confirmed by the Senate on July 31, 1967, and received his commission that day. In 1976, Butzner received the Distinguished Service Award from the Virginia Trial Lawyers Association.