Dev Patel

Gawain

Alicia Vikander

Lady / Essel

Joel Edgerton

Lord

Sarita Choudhury

Mother

Sean Harris

King

Kate Dickie

Queen

Barry Keoghan

Scavenger

Erin Kellyman

Winifred

Ralph Ineson

Green Knight

Anthony Morris

Second Thief

Megan Tiernan

The Young Queen

Brendan Conroy

Taverngoer

Chris McHallem

Lord in Waiting

Atheena Frizzell

Youngest Sister

Donncha Crowley

Bishop

Anaïs Rizzo

Helen

Tara Mae

Middle Sister

Adam Karim

Prince Age 17

Youssef Quinn

Soldier #3 (uncredited)

Janet Grene

Townsfolk (uncredited)

Stuart Mackey

Lancer (uncredited)