Sir Dugald Clerk (sometimes written as Dugald Clark) KBE, LLD FRS (1854, Glasgow – 1932, Ewhurst, Surrey) was a Scottish engineer who designed the world's first successful two-stroke engine
in 1878 and patented it in England in 1881.
He was a graduate of Anderson's University in Glasgow (now the University of Strathclyde), and Yorkshire College, Leeds (now the University of Leeds).
He formed the intellectual property firm with George Croydon Marks, called Marks & Clerk.