- James McAvoy as Professor Charles Xavier / Professor X
- Michael Fassbender as Erik Lehnsherr / Magneto
- Jennifer Lawrence as Raven Darkhölme / Mystique
- Nicholas Hoult as Hank McCoy / Beast
- Oscar Isaac as En Sabah Nur / Apocalypse
- Rose Byrne as Moira MacTaggert
- Tye Sheridan as Scott Summers / Cyclops
- Sophie Turner as Jean Grey: Turner learned archery in preparation for the role.
- Alexandra Shipp as Ororo Munroe / Storm
- Kodi Smit-McPhee as Kurt Wagner / Nightcrawler
- Evan Peters as Peter Maximoff / Quicksilver
- Lucas Till as Alex Summers / Havok
- Ben Hardy as Warren Worthington III / Angel: Hardy practiced indoor skydiving in preparation for his role.
- Lana Condor as Jubilation Lee / Jubilee
- Olivia Munn as Betsy Braddock / Psylocke: Munn practiced swordfighting in preparation for the role.