Lt. Col. William Francis Cyril James Hamilton Napier, 13th Lord Napier, 4th Baron Ettrick DL (9 September 1900 – 23 August 1954) was a Scottish soldier and courtier. He was the eldest son of Francis Napier, the 12th Lord Napier and his wife Hon. Clarice Jessie E. Hamilton, daughter of . He was educated at Wellington College and Sandhurst. He succeeded as Lord Napier and Ettrick and as chief of the name and arms of Clan Napier upon his father's death in 1941. In 1928, he married Violet Muir Newson, and had four children: