As winners, Chelsea would also have been qualified for the 2019–20 UEFA Champions League group stage; however, since they had already qualified after finishing third in the Premier League, the berth reserved was given to the third-placed team of the 2018–19 Ligue 1 (Lyon) – the 5th-ranked association according to next season's access list.

[3] For the first time, the video assistant referee (VAR) system was used in the competition, where it was implemented in the final.

They were unable to defend their title as they advanced to the Champions League knockout stage, and were eliminated by Juventus in the round of 16.

When a place was vacated, it was redistributed within the national association by the following rules:[8] The labels in the parentheses show how each team qualified for the place of its starting round:[13] Notably one team that was not playing a national top division took part in the competition; Vaduz (representing Liechtenstein) played in 2017–18 Swiss Challenge League, which is Switzerland's second tier.

The schedule of the competition was as follows (all draws were held at the UEFA headquarters in Nyon, Switzerland, unless stated otherwise).

[29] Matches in the qualifying (including preliminary and play-off) and knockout rounds could also be played on Tuesdays or Wednesdays instead of the regular Thursdays due to scheduling conflicts.

[11] In the qualifying and play-off rounds, teams were divided into seeded and unseeded teams based on their 2018 UEFA club coefficients (for Main Path),[30] or based on which round they qualified from (for Champions Path), and then drawn into two-legged home-and-away ties.

Notes The draw for the group stage was held on 31 August 2018 at the Grimaldi Forum in Monaco.

For the draw, the teams are seeded into four pots based on their 2018 UEFA club coefficients.

Akhisarspor, Chelsea, F91 Dudelange, Jablonec, Rangers, RB Leipzig, Sarpsborg 08, Spartak Moscow and Spartak Trnava made their debut appearances in the UEFA Europa League group stage (although Chelsea, Rangers, RB Leipzig and Spartak Moscow had already competed in the UEFA Europa League knockout phase after a third place in the UEFA Champions League group stage, while Rangers and Spartak Moscow had appeared in the UEFA Cup group stage).

In the knockout phase, teams played against each other over two legs on a home-and-away basis, except for the one-match final.

The UEFA technical study group selected the following 18 players as the squad of the tournament.

[43] The award winner was announced during the 2019–20 UEFA Europa League group stage draw in Monaco on 30 August 2019.