Williams syndrome (WS) is a neurogenetic developmental disorder characterized by peaks and valleys of cognitive abilities. One peak that has been understudied is the affinity that many individuals with WS have with music. It remains unknown whether their high levels of musical interest, skill, and expressivity are related to their sociable personality or their verbal intelligence. We examined the relationships between musicality (musical interest, creativity, and expressivity), sociability (social-emotionality, social approach), and language comprehension in WS and typically developing (TD) controls. Findings suggest that emotion-expressivity through music in WS may be linked to sensitivity and responsivity to emotions of others, whereas general interest in music may be related to greater linguistic capacity in TD individuals. Musicality and sociability may be more closely related in WS relative to typical development. Implications for future interventions for this neurodevelopmental condition are discussed.