The detection of social threat is crucial for adaptive behaviour. Previous studies have shown that angry faces capture attention and are processed more efficiently than happy faces. While this anger superiority effect has been found in typical and atypical development, it is unknown whether it exists in individuals with Williams syndrome (WS), who show reduced social fear and atypical sociability. In this study, children with WS searched for angry or happy target faces surrounded by 2, 5 or 8 distracters (happy or angry faces, respectively). Performance was compared to that of mental age-matched controls. Results revealed no group differences for happy faces, however for angry faces, the WS, but not the control group, showed a significant performance decrease for the 8-distracters condition, indicating the absence of an anger superiority effect, in good agreement with evidence for abnormal structure and function in brain areas for social threat processing in WS.