The Senior Open Championship, or simply The Senior Open (and originally known as the Senior British Open) is a professional golf tournament for men aged 50 and over. It is run by The R&A, the same body that organises The Open Championship. Prize money won in the event is official money on both the Champions Tour and the European Seniors Tour. In 2010, the prize fund, which is fixed in United States dollars, was $2 million.

The tournament was first held in 1987. It became part of the European Seniors Tour schedule in 1992. In late 2002 it was designated as the fifth major championship on the Champions Tour schedule. All winners before 2003 were not retroactively designated as Champions Tour major winners. Winners gain entry into the following season's Open Championship.

The standard field size is 144 players. An 18-hole qualifying round is held at the championship course on the Monday before the tournament, with a minimum of 24 places available. If fewer than 120 exempt players (see below) enter, the field will be filled to 144 with more high finishers from qualifying. If more than 120 exempt players enter, the top 24 finishers earn entry even if it causes the field to expand beyond 144. If an exempt player withdraws before the start of the tournament, his place will be filled by an alternate who participated in the qualifying round.

The Open Championship, or simply The Open (often referred to as the British Open), is the oldest of the four major championships in professional golf. It is the only major held outside the United States and is administered by the R&A, which is the governing body of golf outside of the U.S. and Mexico.

The Open is played on the weekend of the third Friday in July. It is the third major to take place each year, following the Masters Tournament and the U.S. Open, and precedes the PGA Championship. The current champion is Darren Clarke who won the 2011 Open at Royal St George's Golf Club in Sandwich, Kent. The next Open Championship will be held at Royal Lytham & St. Annes Golf Club in Lytham St. Annes, Lancashire.

The event takes place every year on one of nine links courses in Scotland or England (the event has been held once in Northern Ireland, but Royal Portrush is no longer on the rotation). In 2012, The Open will have a prize fund of £5 million, with £900,000 going to the winner. Historically, The Open's prize money was consistently the least of the four majors, but from 2002 to 2008 it was the highest.