This paper explores sex differences in interpersonal aggression among Aka foragers of the Central African Republic (CAR). We tested whether male Aka physically aggressed more than female Aka, and whether female Aka indirectly aggressed more than male Aka, as evolutionary theories of aggression predict. To our knowledge, these are the first tests of these theories among an extant population of hunter-gatherers. We also tested predictions of a recent evolutionary theory of physical strength, anger, and physical aggression. Data include a measure of upper body strength, age, sex, and qualitative views on aggression norms, as well as peer assessments of anger, physical aggression, and indirect aggression. Our results provide mixed support for the predicted sex differences in physical aggression and indirect aggression, and for the predicted relationships among anger, strength, and the use of aggression.