"We're going to face some great teams, but that's what it's all about," said Legia coach Czesław Michniewicz after the draw, which the European football governing body UEFA held in Istanbul, Turkey, on Friday.
"We want to play in European competition and show our best," he added, as quoted on the club's website.
Legia reached the Europa League after a 2-1 home win over Czech side Slavia Prague on Thursday.
The Polish top-flight club earlier this month saw its hopes of qualifying for the Champions League group stage crushed by Croatian side Dinamo Zagreb.
The Europa League group stage kicks off on September 16.
The final of this season's UEFA Europa League is due to take place in Seville, Spain on May 18, 2022.
2021/2022 Europa League group stage draw in full:
Group A: Lyon, Rangers, Sparta Prague, Brondby
Group B: Monaco, PSV Eindhoven, Real Sociedad, Sturm Graz
Group C: Napoli, Leicester City, Spartak Moscow, Legia Warsaw
Group D: Olympiacos, Eintracht Frankfurt, Fenerbahce, Royal Antwerp
Group E: Lazio, Lokomotiv Moscow, 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, Rapid Vienna
(gs)
Source: PAP, uefa.com