The ability to identify other people’s emotions, including their emotional facial expression (EFE), is fundamental to many social processes. Individuals with autism spectrum disorders (ASD) show deficits in several empathy-related processes, including EFE decoding (e.g. Ashwin, Chapman, Colle, & Baron-Cohen, 2007). The object of this study was to investigate the capacity to decode accurately EFE in siblings of children with ASD. Indeed, autism is considered to be substantially influenced by genetic factors and relatives of ASD individuals present different type of deficits including the domains of language, theory of mind, and executive functioning (e.g., Fombonne, Bolton, Prior, Jordan, & Rutter, 1997). Fifteen 6-to-15 years old siblings of children with ASD were compared to matched siblings of typically developing children on a decoding task of adults EFE. The children had to match a story depicting an adult in an emotional situation to a picture of an adult EFE. The emotions investigated were joy, anger, sadness, fear, surprise, disgust, and contempt. The differences of EFE accuracy between siblings of ASD and siblings of typically developing children are discussed in reference to the characteristics of the relationship with their ASD brother or sister.