Tottenham have been drawn with Anderlecht, Monaco and Azerbaijan side Qarabag in the Europa League group stage, while Liverpool face trips to France, Russia and Switzerland.
An away clash against Rubin Kazan represents a long flight for the Reds, who will also take on Girondins de Bordeaux and Swiss side FC Sion in Group B.
Borussia Dortmund will take on PAOK FC, Krasnodar and another Azerbaijan outfit, Qabaka in Group C, while fellow Bundesliga side, FC Schalke 04, are in Group K along with APOEL, Sparta Praha and Asteras
Napoli were drawn in Group D and take on Club Brugge, who are fresh off a Champions League qualifying defeat to Manchester United, Legia Warsaw and surprise package Midtjyland, who beat Southampton to reach the group stages.
In Group E, Villareal have been handed what seems to be a straightforward group with Plzen, Rapid Wien and Dinamo Minsk, while Athletic Club take on AZ, FC Augsburg and Partizan Belgrade in Group L.
St Etienne will need to get past last year's losing finalists Dnipro, while Lazio will also prove a difficult opponent. Rosenborg round out Group G.
Marseille were grouped with Portuguese side Braga, Czech outfit Liberec and Eredivisie club Groningen in Group F.
Full Europe League Group Stage Draw:
Group A: Ajax, Celtic, Fenerbahce, Molde
Group B: Rubin Kazan, Liverpool, Bordeaux. FC Sion
Group C: Borussia Dortmund, PAOK Salonika, Krasnodar, Gabala
Group D: Napoli, Club Brugge, Legia Warsaw, FC Midtjylland
Group E: Villarreal, Plzen, Rapid Vienna, Dinamo Minsk
Group F: Marseille, Braga, Liberec, FC Groningen
Group G: Dnipro, Lazio, St Etienne, Rosenberg
Group H: Sporting, Besiktas, Lokomotiv Moscow, Skenderbeu
Group I: Basle, Fiorentina, Lech Poznan, Belenenses
Group J: Tottenham Hotspur, Anderlecht, Monaco, FK Karabakh
Group K: FC Schalke 04, Apoel, Sparta Prague, Asteras
Group L: Athletic Bilbao, AZ, FC Augsburg, Partizan Belgrade