Today is: Armed Forces Day Staff reports Armed Forces Day pays tribute to those serving in the U.S. Armed Forces, including those in the Army, Navy, Marines, Air Force, and Coast Guard, as well as those in the National Guard and Reserve. It takes place during Armed Forces Week, which begins the Saturday before the day, and during National Military Appreciation Month, which also includes holidays such as Military Spouse Appreciation Day, V-E Day, and Memorial Day. On July 26, 1947, President Truman signed the National Security Act, which brought the branches of the military under the National Military Establishment. It was renamed the Department of Defense in 1949. President Truman issued a proclamation calling for the first celebration to be held on May 20.