Astor married Lady Violet Mary Elliot-Murray-Kynynmound (28 May 1889 - 3 January 1965) on 28 August 1916. She was the third daughter of Gilbert Elliot-Murray-Kynynmound, 4th Earl of Minto and his wife Lady Mary Caroline Grey. From her previous marriage to Major Lord Charles George Francis Mercer Nairne Petty-Fitzmaurice, who was killed in action at Ypres in 1914, Lady Violet had two children, Margaret and George.