I begin by outlining the ontology of lucky occurrences. Based on the conditions that Aristotle sets on such occurrences, we see that their ontology is populated by accidental unities. Next, I argue that, based on the findings of earlier chapters, Aristotle takes lucky occurrences to be uncaused. I then consider what is sometimes taken to be evidence that lucky occurrences are, in fact, caused. I argue that, in each case, Aristotle’s claims only amount to its being as if something caused a lucky occurrence, which is consistent with there being no cause of such occurrences. I conclude by discussing the ramifications of this account for Aristotle’s physics. Though there is more to accidental causation than luck, the fact that lucky occurrences are uncaused entails that there are more varieties of accidental causation than is normally thought. Ultimately, the case of luck suggests that the standard model of accidental causation is to be expanded: Rather than analyzing accidental causation in terms of causation and accidentality, we should analyze it in terms of causation and sameness.