The 45th Infantry Division was an infantry division of the United States Army, most associated with the Oklahoma Army National Guard, from 1920 to 1968. Headquartered for most of its history in Oklahoma City, Oklahoma, the guardsmen fought in both World War II and the Korean War.

The 45th Infantry Division guardsmen saw no major action until they became one of the first National Guard units activated in World War II in 1941. They took part in intense fighting during the invasion of Sicily and the attack on Salerno in the 1943 Italian Campaign. Slowly advancing through Italy, they fought at Anzio until the capture of Rome. After landing in France during Operation Dragoon, they joined the 1945 drive into Germany that ended the War in Europe.