The Williams syndrome (WS) social phenotype is characterised by a high level of social engagement, heightened empathy and prolonged attention to people's faces. These behaviours appear in contradiction to research reporting problems recognising and interpreting basic emotions and more complex mental states from other people. The current task involved dynamic (moving) face stimuli of an actor depicting complex mental states (e.g., worried, disinterested). Cues from the eye and mouth regions were systematically frozen and kept neutrally expressive to help identify the source of mental state information in typical development and WS. Eighteen individuals with WS (aged 8-23 years) and matched groups of typically developing participants were most accurate inferring mental states from whole dynamic faces. In this condition individuals with WS performed at a level predicted by chronological age. When face parts (eyes or mouth) were frozen and neutrally expressive, individuals with WS showed the greatest decrement in performance when the eye region was uninformative. We propose that using moving whole face stimuli individuals with WS can infer mental states and the eye region plays a particularly important role in performance.