In 1191, Richard the Lionheart (Ian Hunter), the King of England, is taken captive by Leopold V, Duke of Austria while returning from the Third Crusade. Richard’s treacherous brother Prince John (Claude Rains) usurps the throne and proceeds to oppress the Saxons, raising taxes supposedly to pay Richard’s ransom, but in reality to secure his own position.
The only nobleman who opposes him is the Saxon knight Sir Robin of Locksley (Errol Flynn). Robin acquires a loyal follower when he saves Much the Miller’s Son (Herbert Mundin) from being arrested by Sir Guy of Gisbourne (Basil Rathbone) for poaching in Sherwood Forest. At Gisbourne’s castle, Robin boldly tells Prince John, John’s supporters and a contemptuous Lady Marian Fitzwalter (Olivia DeHavilland) that he will do all in his power to oppose John and restore Richard to the throne. Robin then escapes, despite the attempts of John’s men.
Robin and his friend Will Scarlet (Patric Knowles) take refuge in Sherwood Forest and recruit Little John (Alan Hale, Sr.), after John trounces Robin in a bruising quarterstaff bout. Men join their growing band, the Merry Men. Robin meets and provokes the rotund Friar Tuck (Eugene Pallette) into a sword-fight. Then Robin persuades him to join his band of outlaws to provide them with spiritual guidance.
Now known as the outlaw Robin Hood, he binds his men by an oath, to fight for a free England until King Richard returns. They are to rob the rich only to give to the poor, and to treat all women with courtesy, “rich or poor, Norman or Saxon.” In a short time, Prince John’s cronies find themselves harassed and robbed.
One day, Robin and his men capture a large party of Normans transporting tax proceeds through Sherwood. Among Robin’s “guests” are Gisbourne, the cowardly Sheriff of Nottingham (Melville Cooper), and Lady Marian. Marian is at first disdainful of Robin, but becomes convinced of his good intentions and begins to see the reality of the Norman brutality. Eventually Robin allows the humiliated Gisbourne and sheriff to depart Sherwood on foot, dressed in rags, telling them that they have Marian’s presence to thank for his sparing their lives.
Incensed, Prince John furiously accuses the Sheriff and Sir Guy of incompetence. The Sheriff comes up with a cunning scheme to capture Robin by announcing an archery tournament. The Sheriff is sure that Robin will be unable to resist the challenge. All goes as planned: Robin wins, is taken prisoner, and is sentenced to be hanged.
Marian helps the Merry Men to rescue Robin. Later, the outlaw sneaks into the castle to thank her. She and Robin pledge their love for each other, but Marian declines to come away with him because she believes she can help the rebellion better where she is.
King Richard and a few of his knights return to England disguised as pilgrims. At an inn, the Bishop of the Black Canons (Montague Love) overhears one of Richard’s men call him “sire” and hurries to alert Prince John. John and Gisbourne plot to dispose of Richard before he can raise an army. Dickon Malbete (Harry Cording), a degraded former knight, is given the task in return for the restoration of his rank and Robin’s manor and estate.
Marian overhears them and writes a note warning Robin, but Gisbourne finds it and has her arrested. Marian’s nurse, Bess (Una O’Connor), has been romantically involved with Much. She sends him to warn Robin. On his way, Much encounters and kills Dickon after a desperate struggle.
Seeking Robin’s help, King Richard and his escort disguise themselves as wealthy monks and journey to Sherwood Forest. They are quickly accosted by Robin. When Richard assures him that he is traveling on the King’s business, Robin happily invites him to dine. Will finds the injured Much. Much tells Robin of Marian’s peril and that Richard is in England. Robin orders a search. Certain now of Robin’s loyalty, Richard reveals his identity.
Robin devises a plan to sneak his men into the castle. He forces the Bishop of the Black Canons to include his men (disguised as monks) in his entourage. The plan succeeds. During the coronation, a melee breaks out. Robin and Gisbourne engage in a prolonged sword fight, ending with Gisbourne’s death. Robin then rescues Marian from her cell.
John begs for forgiveness, but Richard exiles him and his followers for the remainder of his lifetime. He then pardons the outlaws, ennobles Robin as Baron of Locksley and Earl of Sherwood and Nottingham, and ‘orders’ Robin to marry the Lady Marian.