The Ill-Made Knight is a fantasy novel by British writer T. H. White, the third book in the series The Once and Future King.

Much of The Ill-Made Knight takes place mainly in Camelot, and tells of the adventures, perils and mistakes of Sir Lancelot.

Suspense is provided by the tension between Lancelot's friendship for King Arthur and his love affair with the queen.

This affair leads inevitably to the breaking of the Round Table and sets up the tragedy that is to follow in the concluding book of the tetralogy, The Candle in the Wind.

Lancelot attempts to protect the woman, who denies the charge, by riding in between the two, but the man manages to cut off his wife's head.

Finally, Lancelot comes to a town where the inhabitants beg him to rescue a young woman named Elaine, who is trapped in a tower.

Furious at the loss of his virginity, which he believes has also cost him the ability to work miracles, and frightened at the thought that Elaine might have a baby, he leaves.

Arthur notices that the drop in crime has caused the Knights of the Round Table to fall back into their old habits, especially Gawaine, Agravaine, and Mordred, who find their mother in bed with one of King Pellinore's sons and murder both of them.

The Lerner and Loewe musical Camelot is largely based on The Ill-Made Knight and The Candle in the Wind.