Frederick Schaefer was a German revolutionary and Union Army colonel during the American Civil War.

He was a brigade commander at the battles of Pea Ridge and Stones River where he was killed in action.

During the Kentucky Campaign, Schaefer was on sick leave and his regiment was led by Lieutenant Colonel Bernard Laiboldt.

During the battle of Stones River Schaefer's brigade was initially held in reserve of Sheridan's division.

Not having an adequate supply on hand, Sheridan ordered his brigade commanders to fix bayonets and continue to resist the Confederate attacks.