Arsenal have been drawn with BATE Borisov, Cologne and Red Star Belgrade in the Europa League, while Everton face Lyon, Atalanta and Apollon Limassol.
Everton’s Group E opponents include a 2017 semi-finalist in Lyon, while Atalanta finished fourth in Serie A last season and Apollon of Cyprus came through a play-off against FC Midtjylland.
Arsenal face a 2,800-mile round trip to Borisov to take on BATE, who have been Belarussian champions for 11 years in succession.
Cologne finished fifth in last season’s Bundesliga, 13 points off the top four, while Serbian runners-up Red Star complete Group H.
Early tournament favourites AC Milan will take on Austria Vienna, AEK Athens and Croatian side Rijeka in Group D.
The group stage kicks off on September 14 and runs to December 7, with Lyon hosting the final on May 16, 2018.
The top two teams in each group will advance to a Round of 32, which will include eight third-place teams from Champions League groups.