Appropriate behavior in relation to an object often requires judging whether it is owned and, if so, by whom. The authors propose accounts of how people make these judgments. Our central claim is that both judgments often involve making inferences about object history. In judging whether objects are owned, people may assume that artifacts (e.g., chairs) are owned and that natural objects (e.g., pinecones) are not. However, people may override these assumptions by inferring the history of intentional acts made in relation to objects. In judging who owns an object, people may often consider which person likely possessed the object in the past--such reasoning may be responsible for people's bias to assume that the first person known to possess an object is its owner. (Contains 3 footnotes.)