The 1966 Masters Tournament was the 30th Masters Tournament, held April 7–11 at Augusta National Golf Club in Augusta, Georgia.
Jack Nicklaus, age 26, earned his third Green Jacket in an 18-hole Monday playoff and became the first back-to-back champion at the Masters. He ended regulation at even-par 288, tied with Tommy Jacobs and Gay Brewer. Nicklaus shot a 70 in the extra round on Monday to defeat Jacobs (72) and Brewer (78). Nicklaus' score the previous year in 1965 was significantly lower at 271 (−17), a record which stood for 32 years.
On Sunday, Brewer shot a 33 (−3) on the front nine and then had eight pars as he came to the 72nd hole with a one-shot lead. After hitting his approach shot onto the green, he three-putted from 75 feet (23 m), missing a 5-foot (1.5 m) putt for par to win. This was the last Masters that two-time champion Byron Nelson played in; he shot 76 and 78 and missed the cut by one stroke. The 36-hole cut at 153 (+9) was the highest to date, exceeded only in 1982.
A close friend of Nicklaus was among four that died in a private plane crash in Tennessee on Wednesday, while en route to Augusta from Columbus, Ohio. Nicklaus learned of the incident late that night and responded with a 68 in the first round, but fell back with a 76 on Friday.
It was the fifth of 18 major titles for Nicklaus, and his only successful defense of a major. Three months later, he completed the first of his three career grand slams at Muirfield in the Open Championship. Later back-to-back winners at Augusta were Nick Faldo (1989 and 1990, both playoffs) and Tiger Woods (2001 and 2002).
Terry Dill won the seventh Par 3 contest on Wednesday with a score of 22.
Brewer rebounded and won the tournament the next year, while Nicklaus' attempt at three consecutive titles ended early with a rare missed cut. Jacobs never won a major; he was also a runner-up in the U.S. Open in 1964 at Congressional.
CBS commentator Jack Whitaker referred to the gallery at the end of the 18-hole Monday playoff as a "mob" and was banned from the next five Masters (1967–1971).