Robert Dennis "Denny" Doyle (born January 17, 1944) is a former Major League Baseball second baseman who played for the Philadelphia Phillies (1970-1973), California Angels (1974-1975) and Boston Red Sox (1975-1977). He batted left-handed and threw right-handed. He was considered a good-fielding second baseman but a weak hitter, finishing with a career batting average of .250 and 16 home runs. Doyle enjoyed his best season in 1975, when after being traded from the Angels to the Red Sox in June, he batted .310 in 89 games for the Red Sox, including a league-best 22 game hit streak. He was the starting second baseman for the Red Sox in the 1975 American League Championship Series and World Series.

Doyle has the distinction of having the only hit in three one-hitters in his career, getting the only hit, a lead-off single in the first inning, against Nolan Ryan of the New York Mets on April 18, 1970, and hitting a two-run home run in a game versus the Cincinnati Reds pitched by Gary Nolan on May 24, 1971. Then, on July 18, 1972, against the San Diego Padres, Doyle broke up Steve Arlin's bid for a no-hitter by singling with two out in the ninth inning. Padres manager Don Zimmer pulled in his third baseman to guard against the possible bunt. Doyle then placed a ball over the third baseman's head and Arlin's date with destiny was over. No pitcher has ever tossed a no-hitter in a Padre uniform; to date, this is the closest any has come to pitching one.

Doyle's major league career is perhaps best known for his role in the famous Game Six of the 1975 World Series versus the Cincinnati Reds, which featured Carlton Fisk's dramatic twelfth-inning home run that has become one of baseball's most iconic highlights. Doyle was involved in a ninth-inning play that baseball fans still discuss. The score was tied 6-6 and the bases were loaded with no outs and Doyle on third base when Fred Lynn lifted a fly ball to short left field. After Reds left fielder George Foster made the catch, Doyle tagged up and attempted to score the winning run. He was thrown out at home plate, which inadvertently helped set the stage for Fisk's subsequent game-winning home run. After the game, Red Sox third-base coach Don Zimmer told the press, "I was yelling 'no, no, no' and with the crowd noise, he (Doyle) thought I was saying 'go, go, go.'" In a World Series that included five future Hall of Fame players, Doyle was the only player on either team to hit safely in all seven games.