The 1951 Open Championship was the 80th Open Championship, held from 4–6 July at Royal Portrush Golf Club in County Antrim, Northern Ireland. It was the first played in Northern Ireland and remains the only Open ever held in Northern Ireland, and the only time the event has been held outside England or Scotland. Englishman Max Faulkner won his only major title in the rain, two strokes ahead of runner-up Antonio Cerdá of Argentina.
The maximum number of players making the cut after 36 holes was increased from 40 to 50. Ties for 50th place did not make the cut. With potentially an extra 10 players making the cut and getting £20 prize money the total purse increased from £1,500 to £1,700. The other prizes remained unchanged with £300 for the winner. Only 148 players entered, the lowest since 1904. Qualifying took place on 2–3 July. Entries played 18 holes on the Championship course at Portrush and 18 holes at Portstewart Golf Club. The number of qualifiers was limited to a maximum of 100. Ties for 100th place would not qualify. The qualifying score was 155 and 98 players qualified. Antonio Cerdá led the qualifiers scoring 138 with Tom Haliburton, Bobby Locke and Norman Von Nida next on 139. Peter Alliss qualified comfortably, following up a first round 76 at Portstewart with an impressive 69 at Portrush.
Jimmy Adams and Norman Von Nida shared the lead after the first round with 68. They turned out to be the only sub-70 rounds recorded in the tournament. Faulkner took a two shot lead over Norman Sutton after the second round with Fred Daly and Harry Weetman a further shot behind. After his 69 in qualifying Peter Alliss scored 79 and 80 and missed the cut.
After the third round Faulkner stretched the lead to six over Sutton and Cerdá after a second consecutive 70 in the third round. In the final round Faulkner finished 5-5-4-5 and carded a 74 to post a 285 total. Cerdá was the only player still on the course with a chance to tie. Going out in 34, he reached the 16th needing to play the last three holes in 12 shots. His challenge ended, however, when his drive ended up against some steps straddling a barbed wire fence and he took 6. He finished on 287, two shots behind Faulkner.
Faulkner would be the last Englishman to win the Open Championship for 18 years, until Tony Jacklin in 1969. Frank Stranahan tied for twelfth and was the low amateur for the third straight year, one of two Americans to make the cut. Two Australians made their Open Championship debuts: future five-time champion Peter Thomson finished in 6th place, while 1960 Open champion Kel Nagle placed in 19th.
The 1951 PGA Championship at Oakmont near Pittsburgh concluded on Tuesday, 3 July. This was the second day of the Open Championship qualification, making it impossible to play in the final two majors.