The 2001 United States Open Championship was the 101st U.S. Open, held June 14–18 at Southern Hills Country Club in Tulsa, Oklahoma. The U.S. Open returned to Southern Hills for the first time since 1977. Retief Goosen won the first of his two U.S. Open titles in an 18-hole Monday playoff, two strokes ahead of runner-up Mark Brooks. The tournament was also notable for ending defending champion Tiger Woods' run of four consecutive major championship wins, the "Tiger Slam;" he finished seven strokes back in a tie for twelfth. Woods reclaimed the U.S. Open title the following year, and won the PGA Championship at Southern Hills in 2007.

The total purse was $5 million with a winner's share of $900,000.

At the end of the final round on Sunday, Brooks three-putted his way out of the lead on the 72nd hole. In the final pairing, co-leaders Goosen and Stewart Cink both had approach shots from the 18th fairway. Cink missed the green long and then three-putted from fifteen feet (4.5 m) to double bogey. Goosen had ten feet (3 m) for birdie, but also three-putted to tie Brooks, forcing the next-day playoff.

This U.S. Open was the third at Southern Hills and its sixth major championship. Former Open champions were Tommy Bolt in 1958, and Hubert Green in 1977. The course also previously hosted the PGA Championship in 1970, 1982, and 1994, all played in August, and later hosted the 2007 event.

Lengths of the course in previous major championships:

Sixty-seven players were exempt and the remainder earned their place through sectional qualifying."58 Players Exempt For 2001 U.S. Open". Retrieved June 10, 2023.

1. Last 10 U.S. Open Champions

2. The U.S. Amateur champion