The Wolf in Sheep's Clothing.

“The wolf in sheep’s clothing” is a proverbial label drawn from the Aesopic fable commonly titled “The Wolf in Sheep’s Clothing.” In the story, a wolf disguises itself in a sheepskin to mingle with a flock and prey on them unnoticed; in many versions the ruse ends with the wolf being discovered and killed (often by a shepherd) after it is mistaken for a sheep. The fable belongs to the long, fluid tradition of Aesop’s tales transmitted orally and in many written collections in Greek, Latin, and later European vernaculars, so it is difficult to tie the phrase to a single “original” wording or date. The expression became a standard moral tag for deceptive hypocrisy.

The phrase condenses the fable’s moral into an image of predatory danger masked by apparent innocence. A “wolf” signifies an agent of harm—greed, violence, exploitation—while “sheep’s clothing” represents the social signals of harmlessness, piety, or conformity that win trust. The enduring force of the saying lies in its warning about appearances: ethical judgment should not rely on outward presentation, since malice can imitate virtue. It also implies that deception is ultimately unstable: the disguise may secure short-term advantage, but it invites exposure and punishment once actions reveal true intent. As a proverb, it is applied broadly—from personal relationships to politics and institutions—where benevolent rhetoric conceals self-interest.

A wolf in sheep’s clothing.
A wolf in a sheep’s skin.
Beware of wolves in sheep’s clothing.