Introduction: Parenting children with intellectual and developmental disabilities can be stressful; however, families with religious beliefs may have positive ways of viewing their family. This study explored the associations between religious and spiritual involvement (RSI), family characteristics, parent mental health, and child adaptive and problem behaviors among 180 primary caregivers and their 3-year-old children with developmental delay (DD). Method: This study investigated if RSI was related to family characteristics, parent depression and stress, and if RSI predicted parent mental health after accounting for child and family characteristics. Results: Associations between RSI, family characteristics (parent age, education, income) and parenting stress, but not depression, were found. RSI did not predict parent mental health after accounting for relevant child and family characteristics. Conclusion: RSI may play an important role in the mental health of parents of children with developmental delay; however, other child and contextual factors relate strongly to parent wellbeing.