Monitor was an American weekend radio program broadcast live and nationwide on the NBC Radio Network from June 12, 1955, until January 26, 1975. It began originally on Saturday morning at 8am and continued through the weekend until 12 midnight on Sunday. After the first few months, the full weekend broadcast was shortened when the midnight-to-dawn hours were dropped since few NBC stations carried it. The show was the brainchild of Sylvester (Pat) Weaver, whose career bridged classic radio and television's infancy and who sought to keep radio alive in a television age. Believing that broadcasting could and should educate as well as entertain, Weaver fashioned a series to do both with some of the best-remembered and best-regarded names in broadcasting, entertainment, journalism, and literature taking part. The final sound heard on Monitor was of the "Beacon", followed by the NBC chimes at 5:58:50pm.

About 125 stations still carried the program on its last day, with few in major markets.