The boy who cried "Wolf!" is a popular folktale about a person in charge of watching over sheep to make sure that no wolves take any. On a whim (or in some versions, because of loneliness), the shepherd cries out "Wolf!" and the village people come to help drive the wolf away. As they arrive, he tells them that it has run off.

He does this the next day, and the day after. Eventually, the people's trust in the shepherd is broken, and when a wolf really does come, he cries out "Wolf!" again, but this time nobody answers his call, and so the wolf eats some of his flock (or in some versions, the shepherd himself).

The story serves as a lesson about how much easier it is to break trust than to build it, and how if someone continually lies, nobody will believe them even when they are telling the truth.