Ownership affords different rights and privileges to owners than non-owners. We investigated whether children view transgressions that impose a large or permanent cost to the owner as less acceptable than (1) actions that impose small or temporary costs, and (2) actions that do not impose any costs to owners. Children aged three to eight years (N=72) and adults (N=72) were shown vignettes in which an agent interacts with someone else’s property without permission. Both adults and children judged actions that imposed severe costs to owners as less acceptable than minor transgressions that imposed temporary costs and actions that did not involve physical contact. These findings reveal that children and adults consider the costs imposed on owners when judging the acceptability of people’s interactions with others’ property. Critically, these findings also provide preliminary evidence that children’s concept of ownership may be embedded into their broader social cognitive framework of intuitive psychology.