The 2010 Open Championship was a men's major golf championship and was held from 15 to 18 July over the Old Course at St Andrews, Fife, Scotland. It was the 150th anniversary of the founding of The Open in 1860, and the 28th time The Open was played at St Andrews. Usually branded with the edition of the championship (for example, the previous year's Open was branded as the "138th Open Championship"), due to the sesquicentennial anniversary, the R&A branded this as the "150th Anniversary Open Championship" rather than "139th Open Championship." The standard branding returned the following year.

Louis Oosthuizen won his only major championship with 272 (−16), seven strokes clear of runner-up Lee Westwood. A stroke behind in third were Paul Casey, Rory McIlroy, and Henrik Stenson.

St Andrews is considered to be the home of golf, and as such, the current Open Championship rota means that the Old Course plays host to the championship every five years. Given the course's standing, even more attention is given to The Open whenever it visits the historic links.

The previous two Opens at St Andrews, in 2000 and 2005, were both won by Tiger Woods, the first with a record 19-under-par total. The primary change to the course from 2005 was at the par-4 17th hole; a new tee extended the Road Hole to 495 yards (453 m), an increase of 40 yards (37 m). Although not altered, the measurement angle of the dogleg was revised for hole #7, resulting in a new length of 371 yards (339 m), a reduction of 19 yards (17 m).

Previous lengths of the course for The Open Championship (since 1950):

Each year, around two-thirds of The Open Championship field consists of players that are fully exempt from qualifying for the Open. The players who have already qualified for the 2010 Open Championship are listed below. Each player is classified according to the first category in which he qualified, but other categories are shown in parentheses.

1. Past Open Champions aged 60 or under on 18 July 2010
Mark Calcavecchia, Stewart Cink (2,5,6,16,20), Ben Curtis (2,4), John Daly, David Duval (2), Ernie Els (2,4,5,6,7,16,20), Nick Faldo, Todd Hamilton (2), Pádraig Harrington (2,4,6,7,14,16), Paul Lawrie, Tom Lehman, Justin Leonard (4,5,20), Sandy Lyle, Mark O'Meara, Tom Watson (4,5), Tiger Woods (2,4,6,12,14,16,20)
(Eligible but not playing: Ian Baker-Finch, Seve Ballesteros, Nick Price, Bill Rogers)
(Greg Norman (4) withdrew due to a shoulder injury.)

2. The Open Champions for 2000–2009