 Deep theorizing about possibility requires theorizing about possible objects. One popular approach regards the notion of a possible object as intertwined with the notion of a possible world. There are two widely discussed types of theory concerning the nature of possible worlds: actualist representationism and possibilist realism. They support two opposing views about possible objects. Examination of the ways in which they do so reveals difficulties on both sides. There is another popular approach, which has been influenced by the philosophy of Alexius Meinong. The Meinongian approach is relevant to theorizing about possible objects because it attempts to construct a general theory of objects other than ordinary concrete existing objects. Independently of the debate about the nature of possible worlds or about Meinongianism, it is not always as straightforward as it may at first appear to determine whether putative possible objects are indeed possible. Another category of object similar to that of a possible object is the category of a fictional object. Although initially attractive, the idea that fictional objects are possible objects should not be accepted blindly. An important instance of theoretical usefulness of possible objects is their central role in the validation of two controversial theorems of a simple quantified modal logic.