Infants at elevated likelihood of developing autism display differences in sensory reactivity, especially hyporeactivity, as early as 7 months of age, potentially contributing to a developmental cascade of autism symptoms. Caregiver responsiveness, which has been linked to positive social communication outcomes, has not been adequately examined with regard to infant sensory reactivity. This study examined the multiplicative impact of infant sensory hypo- and hyperreactivity on caregiver responsiveness to sensory reactivity and regulation cues in 43 infants at elevated likelihood of autism. Sensory hyperreactivity was found to moderate the association between sensory hyporeactivity and caregiver responsiveness, such that caregivers of infants with moderately high sensory hypo- and hyperreactivity demonstrated higher responsiveness.