BACKGROUND : Raising a child with special needs challenges mothers in complicated ways, yet, alongside these difficulties, there is evidence for maternal post-crisis growth. Social support is one element that may contribute to growth. OBJECTIVE : This study explores the relationship between social support and post-crisis growth, examines type of disability as a mediating variable between support and growth, and, looks at the relations between subtypes of support and growth. METHODS : Participants included 99 mothers of children with Autism Spectrum Disorder (ASD) and 119 mothers of children with Down Syndrome (DS). Mothers completed three self-report questionnaires: demographic, Multidimensional Scale of Perceived Social Support, and the Stress-Related Growth Scale. RESULTS : Social support was found to predict maternal post-crisis growth with type of disability serving as a mediating variable between them, such that social support contributes to post-crisis growth only among mothers of children with ASD. In addition, results revealed various correlations between types of support and types of growth. CONCLUSIONS : The findings indicate that compared to DS, characteristics of ASD may contribute to less maternal post-crisis growth, and that social support serves as an important predictor for growth in this group. Finding ways to increase social support for mothers of children with ASD thus gains additional importance.