Lew Ayres (December 28, 1908 – December 30, 1996) was an American actor. Born Lewis Frederick Ayre III in Minneapolis, Minnesota and raised in San Diego, California, Ayres began acting in bit player roles in films in 1927. He played opposite Greta Garbo in 1927's The Kiss, but it was his starring role in 1930's All Quiet on the Western Front which made him a star. He played the title role in Young Dr. Kildare in 1938, and became a matinee idol, starring in several Kildare films.

But his conscientious objector status during World War II caused outrage throughout America, until he volunteered with the Medical Corps, serving in the Pacific and in New Guinea. In 1948 he was nominated for the Academy Award for Best Actor for Johnny Belinda, but his career was sparse after the war. He was offered the part of Doctor Kildare in a television series, but his request that the show would not have cigarette ads torpedoed that.

His 1976 documentary film Altars of the World brought his Eastern philosophical beliefs to the screen and earned him critical acclaim.

Ayres was married three times. He was married to actress Lola Lane from 1931 until 1933 and to actress Ginger Rogers from 1934 until 1940. His third marriage, to Diana Hall, lasted from 1964 until his death.

He has a star on the Hollywood Walk of Fame at 6385 Hollywood Blvd.