James Hall Nasmyth (sometimes spelled Naesmyth, Nasmith, or Nesmyth) (19 August 1808 – 7 May 1890) was a Scottish engineer, philosopher, artist and inventor famous for his development of the steam hammer. He was the co-founder of Nasmyth, Gaskell and Company manufacturers of machine tools. He retired at the age of 48, and moved to Penshurst, Kent where he developed his hobbies of astronomy and photography.

In memory of his renowned contribution to the discipline of mechanical engineering, the Department of Mechanical Engineering building at Heriot-Watt University, in his birthplace of Edinburgh, is called the James Nasmyth Building.