The 1948 Open Championship was the 77th Open Championship, held 30 June to 2 July at Muirfield in Gullane, East Lothian, Scotland. Henry Cotton, age 41, won his third and final Open title, five strokes ahead of runner-up and defending champion Fred Daly.
Qualifying took place on 28–29 June. Entries played 18 holes at Muirfield and 18 holes at the number 1 course Gullane. The number of qualifiers was limited to a maximum of 100. Ties for 100th place would not qualify. The qualifying score was 152 and 97 players qualified. Henry Cotton led the qualifiers on 138. Cotton had led the qualification in 1935, the previous time the Open had been held at Muirfield. The maximum number of players making the cut after 36 holes was again set at 40. Ties for 40th place did not make the cut.
Charlie Ward, Sam King, and Flory Van Donck shot 69 to share the first round lead. Henry Cotton opened with a 71, then led by four strokes after a 66 in the second round, one off his own tournament record set in 1934. While scoring conditions in the first two rounds were ideal, with five other rounds of sub-70 in the second, the change in weather on the final day caused scores to soar. Over the final two rounds no player recorded a round below 70. Cotton carded rounds of 75-72 to set a clubhouse lead of 284 that no one came close to matching. Fred Daly came closest with a 289, five-shots behind.
Argentine Roberto De Vicenzo made his Open Championship debut and finished in third place. Over the next two years he followed with another third and a runner-up finish. He would eventually win the title 19 years later, in 1967.