Silas Lee Copeland was a United States Army soldier who served as the third Sergeant Major of the Army. He was sworn in on October 1, 1970, and served until June, 1973.

The sergeant major of the Army (SMA) is a unique non-commissioned rank and position of office in the United States Army. The holder of this rank and position is the most senior enlisted soldier in the Army, unless an enlisted soldier is serving as the senior enlisted advisor to the chairman. The SMA is appointed to serve as a spokesman to address the issues of enlisted soldiers to all officers, from warrant officers and lieutenants to the Army's highest positions. As such, they are the senior enlisted advisor to the chief of staff of the Army. The exact duties vary depending on the chief of staff, though much of the SMA's time is spent traveling throughout the Army, observing training and talking with soldiers and their families.