The UEFA Europa League is an annual football club competition organised since 1971 by the Union of European Football Associations (UEFA) for eligible European football clubs. It is the second-tier competition of European club football, ranking below the UEFA Champions League and above the UEFA Europa Conference League.

The 2004–05 UEFA Cup was the 34th edition of the UEFA Cup. The format of the competition had changed from previous seasons, replacing that from the previous one after the abolition of the Cup Winners' Cup in 1999; an extra qualifying round was introduced, as was a group phase after the first round. The group stage operated in a single round-robin format consisting of eight groups of five teams, each team plays two games at home and two away and the top three finishers of each group progress to the knock-out round, joining the eight third-placed teams from the UEFA Champions League group stage.