Sidney Herbert Elphinstone was born at Carberry Tower south-east of Edinburgh on 27 July 1869.

He was the son of William, 15th Lord Elphinstone and Lady Constance Murray (28 Dec 1838 – 16 Mar 1922).

[5] Lord Elphinstone's Scrap book, which is held in the Mary Ann Beinecke Decorative Art Collection at the Sterling and Francine Clark Art Institute Library, provides a list of the clans of Scotland with the badges of distinction used by them.

Lord Elphinstone married Lady Mary Bowes-Lyon on 24 July 1910 in Westminster.

She was the daughter of Claude Bowes-Lyon, 14th Earl of Strathmore and Kinghorne and Cecilia Cavendish-Bentinck.