Leicester face trips to Italy, Russia and Poland
West Ham will face Dinamo Zagreb, Genk and Rapid Vienna in Group H of the Europa League.
The Hammers are in European competition for the first time since the 2006-07 season and their toughest test will be Zagreb, who beat Tottenham in last season’s round of 16.
They will also go head-to-head with the Belgian side Genk as well as the Austrian outfit Rapid Vienna.
Celtic are in Group G with German giants Bayer Leverkusen, Real Betis and Ferencvaros.
Meanwhile Rangers are back in this competition after failing to make it through the Champions League qualifiers.
They were beaten by Slavia Prague last season and they will return to the Czech Republic capital, having been drawn in Group A against Lyon, Sparta Prague and Brondby.
The group stage kicks off on 16 September, with the schedule due in the next 24 hours, with the final set to be at the Estadio Ramon Sanchez-Pizjuan in Sevilla.
UEFA is reviewing whether away fans will be able to travel, with qualifying fixtures across all three club competitions watched by home fans only.
GROUP A: Olympique Lyonnais, Rangers, Sparta Prague, Brondby
GROUP B: AS Monaco, PSV Eindhoven, Real Sociedad, Sturm Graz
GROUP C: Napoli, Leicester City, Spartak Moscow, Legia Warsaw
GROUP D: Olympiakos Piraeus, Eintracht Frankfurt, Fenerbahce, Royal Antwerp
GROUP E: Lazio, Lokomotiv Moscow, Olympique de Marseille, Galatasaray
GROUP F: Braga, Red Star Belgrade, Ludogorets, Midtjylland
GROUP G: Bayer Leverkusen, Celtic, Real Betis, Ferencvaros
GROUP H: Dinamo Zagreb, Genk, West Ham United, Rapid Vienna