Though Mahler by no means embraced a Nietzschean worldview, the philosopher-psychologist was an important presence in his thinking, both in his student days in Vienna and during his maturity (particularly with the Third Symphony [1896]). This chapter offers a fresh perspective on those ideas of Nietzsche that would have been available to Mahler, whether he interacted with them explicitly or not. These include Nietzsche as idiosyncratic philo-Semite, as left-wing liberator keen to undermine sclerotic social and political conventions, as prophet of the rebirth of ancient dramatic culture in the contemporary German-speaking world, as antagonist of liberalism’s individualist greed through reawakening the emotional elements of a culture, as advocate of the twin impulses of utopianism and self-destruction, and as a post-Wagnerian hoping to supplant the Christian myth of delivery through the Redeemer by his return to ancient Greece.