Alvan Cullem Gillem (July 29, 1830 – December 2, 1875) was a general in the Union Army during the American Civil War.

Although Southern-born, he remained loyal to the Federal government and fought in several battles in the Western Theater before commanding occupation troops in Mississippi and Arkansas during Reconstruction.

Gillem was chief quartermaster of the Army of the Ohio in the several Tennessee campaigns and was brevetted as a major for gallantry in the Battle of Mill Springs.

He was appointed colonel of the 10th Tennessee Infantry in May 1862 and served for a time as the provost marshal of Nashville during the Federal occupation of the city.

In a campaign to protect the loyal mountaineers in East Tennessee, his troops surprised and killed Confederate General John H. Morgan in Greeneville, on September 4, 1864.

He often feuded with the Radical Republicans in the United States Congress over his lenient treatment of ex-Confederate soldiers in his district.