Social support can buffer against stressors often associated with having family members with autism spectrum disorder. This study included 112 parents and typically developing siblings of children with autism spectrum disorder. Relations between self-reported typically developing sibling emotional and behavioral problems and discrepancy between social support frequency and importance were examined via polynomial regression with response surface analysis. Typically developing siblings who described social support as frequent and important reported relatively few problems. Typically developing siblings who reported social support as highly important but infrequent exhibited the highest emotional and behavioral difficulties. Thus, typically developing siblings with little support who view support as highly important may be particularly responsive to social support improvement efforts.