Recent scholarship has placed the concept of friendship at the centre of Aristotle's political thought. However, relatively little attention has been given to Aristotle's claim that political friendship is 'based on equality'. This article first explicates this claim as it appears in the Eudemian Ethics, where Aristotle asserts that the paradigmatic form of political friendship is based on 'arithmetic' rather than 'proportional' equality. Second, it shows that this 'egalitarian' conception of political friendship is fully consistent with theNicomachean Ethics and Politics — and in doing so, challenges a recent argument that the Eudemian Ethics was not genuinely written by Aristotle. Third, it argues that Aristotle's 'egalitarian' conception of political friendship motivates his advocacy of various economic arrangements and practices throughout the Politics, including but not limited to the 'common use' of property.