James Francis Duffalo (born November 25, 1935) is a former American professional baseball player.

He was a member of the 1962 National League champion San Francisco Giants, but did not appear in the 1962 World Series.

[1] Listed at 6 feet 1 inch (1.85 m) and 175 pounds (79 kg), Duffalo entered the professional ranks as a member of the Pittsburgh Pirates' farm system in 1955, winning 17 games as a rookie in the Class D Georgia–Florida League in 1955, then another 16 games in the Class B Carolina League the following season.

Duffalo made his Major League debut on April 12, 1961, for the Giants in a 2–1 win over the Pirates at Candlestick Park.

He was traded to the Cincinnati Reds for left-handed relief specialist Bill Henry on May 4, 1965.