Objectives: Behavioral and emotional problems exhibited by children with intellectual and developmental disabilities (IDD) have been identified as significant stressors for family members in both cross-sectional and longitudinal research. However, there is variability in the extent to which family members are affected by behavioral and emotional problems. In the present study, we explored whether perceived social support, positive perceptions, or coping style explain some of this variability and specifically whether these three variables function as protective factors.Methods: One hundred and thirty-eight mothers of children aged between four and 18 years old with IDD participated in a cross-sectional survey. Results: Using moderated multiple regression models, we found consistent evidence that perceived social support functioned as a protective factor -- affecting the relationship between child behavioral and emotional problems and maternal depression, life satisfaction, and positive affect. There was no evidence that coping and positive perceptions acted as a protective factors. Conclusion: Building social support through parental interventions, especially in families of children with behavioral and emotional problems, may result in improved well-being for mothers of children with IDD.