Timothy John Keefe (January 1, 1857 – April 23, 1933), nicknamed "Smiling Tim" and "Sir Timothy", was an American Major League Baseball pitcher. He stood 5 feet 10 inches (1.78 m) tall and weighed 185 pounds (84 kg). He was one of the most dominating pitchers of the 19th century and posted impressive statistics in one category or another for almost every season he pitched. He was the second MLB pitcher to record 300 wins. He was elected to the Baseball Hall of Fame in 1964.

Keefe's career spanned much of baseball's formative stages. His first season was the last in which pitchers threw from 45 feet, so for most of his career he pitched from 50 feet. His final season was the first season in which pitchers hurled from the modern distance of 60 feet, 6 inches.