Background: Affiliate stigma negatively predicts social support, and positively predicts psychological distress, in caregivers of children with ASD. Whether the affiliate stigma-distress relationship occurs indirectly via social support however has not been explored. Methods: A correlational design was used. A sample of n = 124 caregivers of children with ASD completed an online survey assessing affiliate stigma, perceived support from family, friends and significant others, and perceived stress. Results: The relationship between greater affiliate stigma and increased perceived stress occurred indirectly via lower perceived support from family, but not from friends or significant others. Conclusions: These findings underscore the importance of increasing caregivers' perceived family support. Whether interventions that alleviate affiliate stigma are beneficial for reducing perceived stress, and whether this effect is mediated by increased perceived availability of support, might be the subject of future research.