This study characterized patterns and correlates of parent-youth agreement on social anxiety in youth with and without autism spectrum disorder (ASD). Participants (279 verbally-fluent youth aged 8-16 years, NASD = 144, NTD = 135) completed the SASC-R. Youth with ASD exhibited higher social anxiety across informants. While TD youth endorsed higher anxiety than did parents, self- and parent-reports did not differ in youth with ASD. For children with ASD, higher parent-youth agreement was associated with lower lifetime ASD symptoms and higher adaptive skills. For TD youth, agreement on high anxiety was associated with lowest adaptive skills. Demographic factors (age, verbal IQ, gender) did not relate to agreement for either group. In ASD, parent-child agreement on youth anxiety, either high or low, was associated with better outcomes.