The revival of realism in political theory has included efforts to challenge realism’s conservative reputation and argue that radical forms are possible. Nonetheless these efforts have been criticised as insufficient to overcome realism’s inherent conservatism. This article argues that radical forms of realism can be better appreciated by considering the application of the realist perspective within an existing radical ideology: anarchism. This may seem an unusual choice, considering anarchism’s standard representation as naïvely idealistic and paradigmatically non-realist. However, attention to the breadth of diversity in anarchist theory reveals a collection of positions that together represent a ‘realist anarchism’ which not only challenges anarchism’s reputation as uniformly committed to unrealistic and idealistic utopianism but also demonstrates the existence of genuinely radical forms of realism.