The 2009 PGA Championship was the 91st PGA Championship, held August 13–16 at Hazeltine National Golf Club in Chaska, Minnesota, a suburb southwest of Minneapolis.

Yang Yong-eun, more commonly referred to as "Y.E. Yang" in the U.S., won his only major title, three strokes ahead of runner-up Tiger Woods, a four-time champion. It marked the first (and only) time that Woods had failed to win a major he had led after 54 holes. Yang also became the first Asian-born player to win a men's major championship (although the third of Asian descent, after Vijay Singh and Woods).

It was the fourth major championship held at the course; it previously hosted the PGA Championship in 2002, won by Rich Beem, and two U.S. Opens (1970, 1991). The 2009 course was the longest up to that time for a major at 7,674 yards (7,017 m) (the 2012 and 2021 PGA Championships and 2017 U.S. Open all surpassed it). The average elevation of the course is approximately 940 feet (287 m) above sea level.

Lengths of the course for previous majors:

The following were the qualification criteria that were used to select the field. Each player is listed according to the first category by which he qualified, but other categories are shown in parentheses:

1. All former PGA Champions
Paul Azinger, Rich Beem, Mark Brooks, John Daly, Steve Elkington, Pádraig Harrington (4,6,8), Davis Love III (8,10), Shaun Micheel, Phil Mickelson (3,6,8,9,10), Vijay Singh (8,10), David Toms (6,8), Bob Tway, Tiger Woods (2,3,4,8,10)
(Eligible but not competing: Jack Burke Jr., Dow Finsterwald, Raymond Floyd, Doug Ford, Al Geiberger, Wayne Grady, David Graham, Hubert Green, Don January, John Mahaffey, Larry Nelson, Bobby Nichols, Jack Nicklaus, Gary Player, Nick Price, Jeff Sluman, Dave Stockton, Hal Sutton, Lee Trevino, Lanny Wadkins)

2. Last five U.S. Open Champions
Ángel Cabrera (3,8), Michael Campbell, Lucas Glover (8), Geoff Ogilvy (8,10)

3. Last five Masters Champions
Zach Johnson (8,10)