Ronald Peter Perranoski (born April 1, 1936) is a former left-handed Major League Baseball relief pitcher, having played from 1961 through 1973.

In 1963, Perranoski won 16 of 19 relief decisions for the Los Angeles Dodgers, who would go on to win that year's World Series in four consecutive games over the New York Yankees. He appeared in Game Two of that Series and earned a save in relief of Johnny Podres.

Perranoski grew up in Fair Lawn, New Jersey, where he attended Fair Lawn High School.

Perranoski attended Michigan State University, where he was a teammate and friend of Dick Radatz, who also would become a standout reliever in the 1960s. After his playing career ended, Perranoski was the Dodgers' minor league pitching coordinator (1973-80), then the MLB pitching coach for Los Angeles for 14 seasons (1981-94). He joined the San Francisco Giants as minor league pitching coordinator in 1995, was promoted to bench coach in 1997 and then to pitching coach in 1998-99. He has been a special assistant to general manager Brian Sabean since 2000.

In 1983, Perranoski was inducted into the National Polish-American Sports Hall of Fame.