We sought to clarify the nature of the face processing strength commonly observed in individuals with Williams syndrome (WS) by comparing the face recognition ability of persons with WS to that of persons with autism and to healthy controls under three conditions: Upright faces with neutral expressions, upright faces with varying affective expressions, and inverted faces with neutral expressions. No differences were observed under the upright/neutral expression condition. However, the WS group was more accurate than the autism group when discriminating upright faces with varying affective expressions, whereas the opposite pattern emerged when discriminating inverted faces. We interpret these differences as a reflection of the contrasting social features of the two syndromes.