Ronald Ames Guidry (pronounced /ˈɡɪdri/; born August 28, 1950, in Lafayette, Louisiana; nicknamed "Louisiana Lightning" and "Gator") is a former Major League Baseball left-handed pitcher. He played 14 seasons for the New York Yankees from 1975 through 1988. Guidry was the pitching coach of the New York Yankees from 2006 to 2007.
Guidry began his career pitching briefly in the 1975 and 1976 seasons. In 1977, he began as a relief pitcher but was moved into the starting rotation. He helped lead the New York Yankees to a World Series championship in 1977 and 1978. In those two years combined, Guidry went 4-0 in the postseason with 3 complete games in 5 starts, allowing only nine earned runs in 37 1/3 innings pitched.
In 1978, Guidry posted a career year, one of the best in the modern era. Against the California Angels on June 17, he struck out a Yankee-record 18 batters. Guidry's 18-strikeout performance is usually cited as the launching pad of the Yankee Stadium tradition of fans standing and clapping for a strikeout with two strikes on the opposing batter.