William Debenham was the founder of Debenhams, one of the largest retailers in the United Kingdom. Born in 1794 in Alpheton in Suffolk; William Debenham joined Thomas Clark in a partnership to manage a draper's store at 44 Wigmore Street in London.

The partners later expanded the business such that it had stores on both sides of Wigmore Street, one known as Debenham & Clark and the other known as Clark & Debenham. When William Debenham Snr retired a new partnership was formed between his son, William Debenham Jnr, and Clement Freebody. This business became Debenhams, one of the largest retailers in the United Kingdom. Meanwhile, Thomas Clark went on to form Cavendish House which was later absorbed into House of Fraser. William Debenham Snr died in 1863 at Kensal Rise in London.