Harry Smith Wainwright (16 November 1864 – 19 September 1925) was an English railway engineer, and was the Locomotive, Carriage and Wagon Superintendent of the South Eastern and Chatham Railway from 1899 to 1913. He is best known for a series of simple but competent locomotives produced under his direction at the company's Ashford railway works in the early years of the twentieth century. Many of these survived in service until the end of steam traction in Britain in 1968, and are regarded as some of the most elegant designs of the period.