William Andrew Quarles (July 4, 1825 – December 28, 1893) was a Tennessee lawyer, politician, railroad executive, and a general in the Confederate States Army during the American Civil War.

He was appointed President of the Memphis, Clarksville and Louisville Railway Company, and helped oversee the construction of railroad lines in Tennessee and Kentucky.

With the outbreak of the Civil War, Quarles organized the 42nd Tennessee Infantry and was commissioned on November 28, 1861, as its first colonel.

After being sent to Vicksburg, Mississippi, in early August 1862 and formally exchanged, Quarles resumed command of his regiment.

Quarles was promoted on August 25, 1863, to brigadier general and given command of a brigade initially consisting of the 42nd, 46th, 48th, and 53rd Tennessee infantry regiments, serving in the division of Edward C. Walthall.

After recovering, Quarles led his brigade into Tennessee when army commander John Bell Hood moved northward from Atlanta.

Resuming his own political career, Quarles failed to garner enough support for the United States Senate in 1874, finishing well behind former President Andrew Johnson in balloting in the Tennessee legislature.