This was the sixth consecutive title won by an English team between the UEFA Cup and the Inter-Cities Fairs Cup, as well as the first time Liverpool won a European competition.
A total of 63 teams from 29 UEFA member associations participate in the 1972–73 UEFA Cup. A new allocation scheme was devised by UEFA, which featured fixed slots for all but two competing associations, and lasted for eight seasons:
3 associations have four teams qualify.
3 associations have three teams qualify.
18 associations have two teams qualify.
7 associations have one team qualify.
Spain was the only association with a fixed allocation of three teams; the other two associations would rotate on a yearly basis among all countries that were allocated two teams.
Albania was not included in this scheme, as it had only entered the competition once without playing and would not have a UEFA Cup competitor until 1981. Northern Ireland withdrew from the competition, so another association was granted an extra third birth for this season. The three chosen associations were France, Yugoslavia and Portugal.
Wales: There was no national league in Wales before 1992 and the only competition organised by the Football Association of Wales was the Welsh Cup so Wales had just a single participant in European competitions, the winner (or best placed Welsh team as several English teams also competed) of the Welsh Cup which competed in the UEFA Cup Winners' Cup.
Northern Ireland: Due to the Troubles and the aftermath of the Bloody Sunday, Northern Ireland withdrew from all European competitions on safety grounds. Portadown would have qualified for the UEFA Cup by league position.
Albania: After withdrawing its team from the previous edition, Albania was punished with a one-year ban for the UEFA Cup. 17 Nëntori would have qualified by league position.
West Germany: The fourth UEFA Cup spot for West Germany was not awarded to the fourth best team not qualified for the European Cup or the European Cup Winners' Cup, which was Hertha BSC, as it was common practice. Instead, this place was awarded to Kaiserslautern, who had been runners-up in the 1971–72 DFB-Pokal.
Finland: Official UEFA records show HJK Helsinki as the Finnish representative in the UEFA Cup, despite finishing 4th in the 1971 Mestaruussarja, before withdrawing from its first round match-up.[2] However, records from the RSSSF, contemporary papers and the Football Association of Finland show that HIFK Helsinki was indeed the team that withdrew from the tournament after finishing 2nd in the Mestaruussarja.[3][4][5] While no official reason for the withdrawal has been provided, HIFK ran into financial problems during the 1972 season and was fighting to avoid relegation at the time of the UEFA Cup first round. The team was finally relegated on 24 September 1972, halfway through what should've been its European participation.[6]