| Dennis O'Toole | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 13 March 1949 |
| Birth Place: | Chicago, Illinois |
| Debutleague: | MLB |
| Debutdate: | September 8 |
| Debutyear: | 1969 |
| Debutteam: | Chicago White Sox |
| Finalleague: | MLB |
| Finaldate: | June 23 |
| Finalyear: | 1973 |
| Finalteam: | Chicago White Sox |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0–0 |
| Stat2label: | Earned run average |
| Stat2value: | 5.04 |
| Stat3label: | Innings |
| Stat3value: | 30⅓ |
| Teams: | |
Dennis Joseph O'Toole (born March 13, 1949) is an American former professional baseball player. A right-handed relief pitcher and the younger brother (by 12 years) of National League All-Star lefthander Jim O'Toole, Dennis appeared in 15 Major League games spread over five seasons (1969–1973) for the Chicago White Sox. He stood 6feet tall and weighed .
In 30⅓ MLB innings pitched, O'Toole gave up 43 hits and ten bases on balls, with 22 strikeouts and no saves. He yielded 17 earned runs for a career ERA of 5.04. He compiled a 53–39 (3.66) mark in 211 minor league games, mostly in the White Sox' farm system, over nine seasons (1967–1975).[1] His MLB career did not overlap with Jim's, who hurled his last big league game with the ChiSox over two years before Dennis' debut.