Jack Entratter (February 28, 1914 – March 11, 1971), nicknamed "Mr. Entertainment", was an American business executive. He is best known for management positions at the Copacabana nightclub in New York City in the 1940s and early 1950s, and at the iconic Sands Hotel and Casino in Las Vegas from the early 1950s. He is closely associated with Frank Sinatra and the Rat Pack in the history of Las Vegas, Nevada.