 He was a member of the Executive Committee of the Standing Council of the Baronetage, of the Smeatonian Society of Civil Engineers, the Royal Institution, the Pilgrims, and the Tennyson Society.Tennyson d'Eyncourt married Pamela Gladstone, the younger daughter of William Buckley Gladstone, of Moor Town House, Ringwood, Hampshire, at St Margaret's, Westminster, on 1 June 1926, and they had two sons and one daughter, Philippa, who married Nigel Nicolson.He married secondly, in 1964, Vinnie Lorraine, the widow of Robert J. O'Donnell and younger daughter of Andrew Pearson, of Minneapolis, Minnesota, USA.