The Connacht Senior Football Championship, known simply as the Connacht Championship and shortened to Connacht SFC, is an annual Gaelic football competition for the senior county teams of Connacht GAA. All of the county teams of Connacht participate in the championship, as well as London and New York. The winning team receives the Nestor Cup.
The Connacht SFC is run on a knock-out basis through which teams are eliminated from the competition. A series of games are played during the summer months and the final is played in June or July. The winner and runner-up progresses directly to the All-Ireland SFC Group Stage. Before 2020, all losing teams progressed to the All-Ireland SFC Qualifiers, while, prior to 2001, the All-Ireland SFC was a straight knock-out format, which meant all losing teams were eliminated after a single defeat.
Galway are the three-time title holder, having defeated Mayo by 0–16 to 0–15 in the 2024 final.
Galway are Connacht's most successful county, with 50 Connacht SFC titles and 9 All-Ireland SFC titles. Mayo are next, with 47 Connacht SFC titles and 3 All-Ireland SFC titles. Roscommon have won the Connacht SFC title 24 times, most recently in 2019, as well having won 2 All-Ireland SFC titles. Apart from those three, no other team competing in Connacht has won an All-Ireland SFC title.
Sligo have won the Nestor Cup three times, most recently in 2007. Leitrim have won the competition twice, most recently in 1994.
London have competed in the Connacht SFC since 1975, while New York joined in 1999. In this time London have managed three victories: one in 1977 and two in 2013, against Sligo and Leitrim. New York recorded their first, and, so far, only, victory in the championship over Leitrim in 2023.
The competing counties play for the JJ Nestor Cup, which is presented to the winning captain on Connacht Final Day.