Leonard "Lenny" Patrick (October 6, 1913 - March 1, 2006) was an American mobster, and a member of the Chicago Outfit, he was involved in bookmaking and extortion and later turned government informant.
Emigrating with his family from England, Patrick grew up in the Jewish neighborhood of Lincoln Park, in Chicago's Near North Side and during Prohibition, eventually becoming an associate and later partner of Greek-American loanshark and extortionist Gus Alex. Imprisoned during the 1930s for bank robbery in Indiana, as well as his participation in six suspected gangland slayings, Patrick continued working for the Chicago Outfit and, by the 1950s, his Westside restaurant was one of the biggest bookmaking operations in the city. He would also expand into legitimate front businesses, primarily laundry companies, for illegal gambling, loansharking and extortion activities.
In 1992, Patrick agreed to become a government witness following his indictment for racketeering charges. His testimony would result in the conviction of Gus Alex and several other key figures involved in the city's extortion rackets.