John Eugene O'Donoghue (born October 7, 1939) is an American former Major League Baseball left-handed pitcher. He was signed by the Kansas City Athletics as an amateur free agent before the 1959 season and pitched for the Athletics (1963–1965), Cleveland Indians (1966–1967), Baltimore Orioles (1968), Seattle Pilots / Milwaukee Brewers (1969–1970), and Montreal Expos (1970–1971). During his nine-year major league career, O'Donoghue compiled 39 wins, 377 strikeouts, and a 4.07 earned run average. At the plate, he was 35-for-206 (.170) with 3 home runs, the first two against Buster Narum and the third off Denny McLain.