Some, but not all, relevant studies have revealed face processing deficits among those with autism spectrum disorder (ASD). In particular, deficits are revealed in face processing tasks that involve emotion perception. The current study examined whether either deficits in processing emotional expression or deficits in processing social cognitive complexity drive face processing deficits in ASD. We tested adults with and without ASD on a battery of face processing tasks that varied with respect to emotional expression processing and social cognitive complexity. Results revealed significant group differences on tasks involving emotional expression processing, but typical performance on a non-emotional but socially complex task. These results support an emotion processing rather than a social complexity explanation for face processing deficits in ASD.