An epic fantasy adventure based on the timeless Arthurian legend, The Green Knight tells the story of Sir Gawain, King Arthur's reckless and headstrong nephew, who embarks on a daring quest to confront the eponymous Green Knight, a gigantic emerald-skinned stranger and tester of men.
| Actor | Role |
|---|---|
 Dev PatelGawain | Gawain |
 Alicia VikanderLady / Essel | Lady / Essel |
 Joel EdgertonLord | Lord |
 Sarita ChoudhuryMother | Mother |
 Sean HarrisKing | King |
 Kate DickieQueen | Queen |
 Barry KeoghanScavenger | Scavenger |
 Erin KellymanWinifred | Winifred |
 Ralph InesonGreen Knight | Green Knight |
| EEmilie HetlandFirst Thief | First Thief |
 Anthony MorrisSecond Thief | Second Thief |
 Megan TiernanThe Young Queen | The Young Queen |
| HHelena BrowneSightless Woman | Sightless Woman |
 Brendan ConroyTaverngoer | Taverngoer |
 Chris McHallemLord in Waiting | Lord in Waiting |
 Atheena FrizzellYoungest Sister | Youngest Sister |
 Donncha CrowleyBishop | Bishop |
| NNoelle BrownMadam | Madam |
 Anaïs RizzoHelen | Helen |
| JJoe AndersonParis | Paris |
| NNita MishraOlder Sister | Older Sister |
 Tara MaeMiddle Sister | Middle Sister |
| SSam Uppal LynchPrince Age 7 | Prince Age 7 |
 Adam KarimPrince Age 17 | Prince Age 17 |
| RRuth PatelPrincess Age 4 | Princess Age 4 |
| RRose PatelPrincess Age 6 | Princess Age 6 |
| EEmmet O'BrienMagician | Magician |
| AAndrea DeaskovicGiant | Giant |
| AAoibheann GarryGiant | Giant |
| IIsabel FriosiGiant | Giant |