The All-Ireland Senior Football Championship 2005, known for sponsorship reasons as the 2005 Bank of Ireland All-Ireland Senior Football Championship was the premier Gaelic football competition in 2005. It consisted of 33 teams and began on Saturday 7 May 2005. Few surprises came during the championship with the dominance of the Ulster teams evident once again. Gaelic football's "Big Three" of this era – Armagh, Kerry, Tyrone – all progressed to the semi-finals.

The Championship concluded on Sunday 25 September 2005 when Tyrone defeated Kerry, who were playing in their second consecutive All-Ireland Final, by a scoreline of 1–16 to 2–10. Tyrone had to play ten games (including three replays) in order to win the Championship – more than any other team before or since.

Since the introduction of the so-called "back-door" system a few years ago, a number of changes have taken place in the championship format. In 2005 the following system was used.

The provincial championships in Munster, Leinster, Ulster and Connacht ran as usual on a "knock-out" basis. These provincial games were then followed by the "Qualifier" system:

The All-Ireland Quarter-finals: Each of the four Provincial Champions played one of the four winners from Round 4. The All-Ireland Semi-finals shall be on a Provincial rots basis, initially determined by the Central Council. If a Provincial Championship winning team is defeated in its Quarter-final, the team that defeats it shall take its place in the semi-final.

The losers of the Preliminary round matches and quarter final matches of each provincial championship started the qualifier.

The winners of round 1 were joined by the semi-final losers of each provincial championship. The matches would be between a round 2 winner and a provincial championship semi final loser.

The winners of round 2 contest as the matches from here were lowered to four. Matches were open.