Duncan Gordon Boyes was born on 5 November 1846 in Cheltenham, Gloucestershire, to John and Sabina Boyes, who had married in Hobart, Tasmania. His father was a merchant, and Boyes was one of nine children. In 1860, Boyes' sister, Louisa Mary, married Thomas James Young, who received a Victoria Cross for his actions at Lucknow, India, in 1857. At least one of his brothers also served in the Royal Navy.