The Hammers are in the competition for the first time in five seasons - when they lost to Romanian minnows Astra Giurgiu for the second season running - and the group stage for the first time.
The Foxes once again missed out on Champions League football on the final day of the domestic season, but are considered one of the favourites to win this competition.
Here’s everything you need to know...
When is the Europa League draw?
Date: The Europa League group-stage draw takes place on Friday, August 27, 2021 in Istanbul, Turkey.
UK time: The draw will commence at 11am BST.
How to watch the Europa League draw in the UK
TV channel: The draw will be broadcast live on BT Sport.
Live stream: The Uefa website and BT Sport website will stream the draw online, while Standard Sport will bring you all the drama on our LIVE blog.
Which teams have qualified?
Pot 1: Lyon, Napoli, Bayer Leverkusen, Lazio, Dinamo Zagreb, Olympiacos, Monaco, Braga
Pot 2: Celtic, Eintracht Frankfurt, Red Star Belgrade, Leicester City, Rangers, Lokomotiv Moscow, Genk, PSV
Pot 3: Ludogorets, Marseille, West Ham, Real Sociedad, Real Betis, Fenerbache, Spartak Moscow, Sparta Prague
Pot 4: Rapid Wein, Galatasaray, Legia Warsaw, Midtjylland, Ferencvaros, Royal Antwerp, Sturm Graz, Brondy
Europa League draw rules
The 32 qualified teams will be split across four pots of eight based on club coefficient rankings.
As ever, clubs from the same league cannot be drawn into the same group.
Europa League group-stage fixture dates
Matchday 1 | 16 September
Matchday 2 | 30 September
Matchday 3 | 21 October
Matchday 4 | 4 November
Matchday 5 | 25 November
Matchday 6 | 9 December