I argue in this thesis that central to Nietzsche’s conception of friendship is Mitfreude or shared joy, and that understanding Mitfreude helps us to understand Nietzsche’s ethics more generally. I explore Nietzsche’s focus on shared joy as an explicit response to the prominence of suffering and compassion in the philosophy of Arthur Schopenhauer, portraying Nietzsche’s turn towards joy as integral to his philosophical development away from that figure’s influence. A morality that begins with suffering, Nietzsche suggests, bars us from any perspective on our human situation that would endow with significance our finite projects, and so disenables the ethical work of becoming what we are which relies on those projects. The capacity of friends to share in each other’s joy is, for Nietzsche, a reminder of the possibility of systems of relationality different from that of modern morality. I discuss Nietzsche’s interest in the agonal aspects of Greek culture, understanding relationships of contest, performance, and communal creation as expressions of the type of affirmative relationship to existence Nietzsche applauds. The type of relationality fostered in healthy friendships helps us towards what Nietzsche understands as a proper human self-understanding as a being that becomes. I draw on Nietzsche’s account of friendship to show that in his moral thought Nietzsche maintains a place for other-regarding motives, but that, rather than the erasure of otherness Nietzsche diagnoses in Schopenhauer’s compassion, Nietzsche seeks to treat the sufferings of others in their particularity.