Trespass to chattels is a tort whereby the infringing party has intentionally (or, in Australia, negligently) interfered with another person's lawful possession of a chattel (movable personal property). The interference can be any physical contact with the chattel in a quantifiable way, or any dispossession of the chattel (whether by taking it, destroying it, or barring the owner's access to it). As opposed to the greater wrong of conversion, trespass to chattels is argued to be actionable per se.

The origin of the concept comes from the original writ of trespass de bonis asportatis. As in most other forms of trespass, remedy can only be obtained once it is proven that there was direct interference regardless of damage being done, and the infringing party has failed to disprove either negligence or intent.

In some common-law countries, such as the United States and Canada, a remedy for trespass to chattels can only be obtained if the direct interference was sufficiently substantial to amount to dispossession, or alternatively where there had been an injury proximately related to the chattel. (See Restatement (Second) of Torts, 1965.)