Sylvester and the Magic Pebble is a children's picture book written and illustrated by William Steig, and published in 1969.

Sylvester Duncan, a young donkey from the fictional community of Oatsdale, collects pebbles "of unusual shape and color."

Immediately afterward, a lion scares Sylvester, and as a defense he wishes himself into a rock--the only thing he could think of at the moment.

The rest of the story deals with the resulting aftermath: Sylvester's personal attempt to change back into his true self and Mr. and Mrs. Duncan's search for their only child.

The book sparked some controversy, for its portrayal of the police as pigs, and, as a result was not stocked by public schools and libraries in parts of the United States.