Mohamed Lahyani (born 27 June 1966) is a Swedish tennis umpire. He is a Gold Badge Chair Umpire certified by the Association of Tennis Professionals. He is noted for presiding over the longest match in professional tennis history at the 2010 Wimbledon Championships. He was briefly suspended in 2018 for words of encouragement to Nick Kyrgios during a US Open match between Kyrgios and Pierre-Hugues Herbert.