Social participation is an important resource for parents in old age, and may be particularly important for parents living with adult offspring with intellectual and developmental disabilities. To evaluate whether socializing with friends and family and participating in social organizations protects against depression in old age, this study examined parents of adult offspring with disabilities (n = 164) and without disabilities (n = 820). As expected, more socializing with friends and more participating in organizations were associated with fewer depressive symptoms for all parents. However, socializing with family members predicted fewer depressive symptoms only for parents co-residing with their adult offspring with disabilities, suggesting that socializing with family is particularly important for parents providing direct care to adults with disabilities.