Walter Montgomerie Neilson (28 November 1819 – 8 July 1889) was a noted Scottish locomotive and marine engineer and manufacturer. He was born in Glasgow, the son of James Beaumont Neilson, inventor of the hot blast furnace. Walter was trained as an engineer in the Oakbank Foundry run by his uncle John Neilson. He also worked in the St Rollox Engine Works in Glasgow. He was a President of the Institution of Engineers and Shipbuilders in Scotland and a member of the Institution of Civil Engineers. Outside his professional career, he was involved in local politics, the military, and Freemasonry.