Étienne Lenoir, Belgian engineer, designed the internal combustion engine (d. 1900)
Jean Joseph Étienne Lenoir, also known as Jean J. Lenoir (12 January 1822 – 4 August 1900), was a Belgian-French engineer who developed the internal combustion engine in 1858. Prior designs for such engines were patented as early as 1807 (De Rivaz engine), but none were commercially successful. Lenoir's engine was commercialized in sufficient quantities to be considered a success, a first for the internal combustion engine.

He was born in Mussy-la-Ville (then in Luxembourg, part of the Belgian Province of Luxembourg since 1839). In 1838, he immigrated to France, taking up residence in Paris, where he developed an interest in electroplating. His interest in the subject led him to make several electrical inventions, including an improved electric telegraph.