After coming through three qualification ties, competition debutants Wolves have been drawn in Group K alongside Besiktas, Braga and Slovan Bratislava.
Arsenal will also face Portuguese opposition in Vitoria, as well as travelling to Germany and Belgium for Group F match-ups against Eintracht Frankfurt and Standard Liege respectively.
Man Utd, the winners of the 2016/17 competition, are in Group L where they will meet teams from Kazakhstan, Serbia and the Netherlands.
Arsenal, Eintracht Frankfurt, Standard Liege, Vitoria.
Besiktas, Braga, Wolves, Slovan Bratislava.
Man Utd, Astana, Partizan, AZ Alkmaar.