Glenn Everell Mencer (May 18, 1925 – April 17, 2007) was a United States federal judge.
Mencer was born in Smethport, Pennsylvania. He received his Bachelor of Business Administration from University of Michigan's Ross School of Business in 1949 and his J.D. from University of Michigan Law School in 1952. He served in the United States Army from 1943 to 1945. He was in private practice of law in Eldred, Pennsylvania from 1953 to 1964. He served as district attorney of McKean County, Pennsylvania from 1956 to 1964. He was the presiding judge of the McKean County Court of Common Pleas, 48th Judicial District of Pennsylvania from 1964 to 1970. He was a judge to the Commonwealth Court of Pennsylvania, Harrisburg from 1970 to 1982.
Mencer was a federal judge to the United States District Court for the Western District of Pennsylvania. Mencer was nominated by President Ronald Reagan on February 19, 1982, to a seat vacated by Daniel John Snyder, Jr.. He was confirmed by the United States Senate on March 18, 1982, and received his commission the next day. He assumed senior status on April 18, 1994. His service on the bench was terminated on April 17, 2007, due to death.