Stephen Ailes (May 25, 1912 – June 30, 2001) was a lawyer, and served as Under Secretary of the Army in the Kennedy administration and Secretary of the Army in the Johnson administration.

Born in Romney, Ailes was the grandson of Governor John Jacob Cornwell and older brother of John Ailes, longtime publisher of Romney's Hampshire Review. In his youth Ailes attended Episcopal High School in Alexandria, Virginia. He attended Princeton University, graduating in 1933, and entered law school at West Virginia University, completing his degree in 1936. From 1937-1940 Ailes was a professor at WVU, counting among his students Clarksburg native and future U.S. ambassador Joseph Farland. From 1940-1942, Ailes practiced law in Martinsburg. He later worked for the Office of Price Administration before joining the law firm Steptoe & Johnson in 1948. Ailes did not serve in World War II, as he was colorblind.

On February 9, 1961, Ailes began serving as Under Secretary of the Army in President John F. Kennedy's administration. Ailes was offered the position by Elvis Stahr Jr., Kennedy's newly appointed Secretary of the Army and former president of WVU. In 1962 Stahr was replaced by Cyrus Vance, a fellow West Virginian with whom Ailes worked closely for the next two years. As under secretary, Ailes witnessed such notable events as the failed Bay of Pigs invasion and the Cuban Missile Crisis. He had a reputation, despite his older age, of joining younger soldiers in the field and working and training alongside them.

In November 1963, Ailes presented a resignation letter to Secretary Vance before departing on a diplomatic trip to Panama. Vance suggested Ailes wait until his return before submitting the resignation to the president. Ailes was in Panama on November 22, 1963, the day of President Kennedy's assassination. Following the assassination President Lyndon B. Johnson asked all administration officials to remain on to the end of the year, and Ailes withdrew his resignation.

In January 1964, Ailes was appointed Secretary of the Army following Vance's appointment as Deputy Secretary of Defense. On the day of his appointment riots broke out in Panama; President Johnson joked to Ailes that perhaps the two events were connected. As secretary, Ailes helped negotiate a resolution to these riots, and later oversaw the first deployment of American troops to Vietnam. Ailes was also instrumental in the formation of the Army's Drill Sergeant program. The Army's Stephen Ailes Award, presented annually to an outstanding drill sergeant of the Army, is named in his honor.

Following his time as secretary, Ailes returned to practicing law. He was a member of the Panama Canal Company's board from 1966-1970 and also served as president of the Association of American Railroads from 1971-1977. He served on the Intelligence Advisory Board and Intelligence Oversight Board under President Gerald Ford.

Stephen Ailes married Helen Wales on June 24, 1939, and they had four children. Following a series of strokes, Ailes died in Bethseda, Maryland, at the age of 89 due to congestive heart failure. He is buried in Romney's Indian Mound Cemetery.