Sword of the Valiant: The Legend of Sir Gawain and the Green Knight (often shortened to Sword of the Valiant) is a 1984 dramatic fantasy film directed by Stephen Weeks and starring Miles O'Keeffe, Trevor Howard, Lila Kedrova, Cyrielle Clair, Leigh Lawson, Peter Cushing, and Sean Connery.

The film is loosely based on the poem Sir Gawain and the Green Knight, written in the late 14th century, but the narrative differs substantially.

Promising to return in one year to claim his side of the bargain, the Green Knight gives Gawain a chance to solve a riddle to save his life, which consists of four lines: With King Arthur's blessing, Gawain leaves with Humphrey, a squire, in search of the answer to the Green Knight's riddle.

Morgan le Fay instructs Gawain to blow a horn near the seashore, and to go to the lost city of Lyonesse.

Gawain agrees to follow the rules of the game, and is transported to Lyonesse by the sage, only to find the city decrepit, the denizens old and covered in cobwebs, frozen in time.

Gawain encounters Humphrey, but while away from the house, Linet is kidnapped by the lustful prince Oswald and the army of his father, the warmongering Baron Fortinbras.

Mournful, Gawain leaves Humphrey and the escaped prisoners, wandering aimlessly until he stumbles across the castle of Sir Bertilak.

Gawain has failed to solve the final line of the riddle within the time limit, and must allow the Green Knight one swing at his neck with an ax.

Filming took place in Wales and Ireland, as well as the Château de Pierrefonds and the Palais des Papes in France.

The period wardrobe was culled from the collections of stock rooms of the Royal National Theatre and the Bristol Old Vic as well as Berman's and Nathan's, the French Aristide Boyer and the Spanish Cornejo.

Director Stephen Weeks hoped to cast Mark Hamill as Gawain, but producers Menahem Golan and Yoram Globus insisted on Miles O'Keeffe for the role.