The present work investigated young children's normative understanding of property rights using a novel methodology. Two- and 3-year-old children participated in situations in which an actor (1) took possession of an object for himself, and (2) attempted to throw it away. What varied was who owned the object: the actor himself, the child subject, or a third party. We found that while both 2- and 3-year-old children protested frequently when their own object was involved, only 3-year-old children protested more when a third party's object was involved than when the actor was acting on his own object. This suggests that at the latest around 3 years of age young children begin to understand the normative dimensions of property rights. (Contains 2 tables and 2 figures.)