Social strain has been identified as a trigger for both depression and physical health problems, but has not been well researched in people with intellectual disability (ID). The present study contrasted the effects of social support with social strain on depressive symptoms, somatic complaints and quality of life over time in adults with mild ID. The level of social support explained a significant proportion of variance in quality of life 6 months later, but not depressive symptoms or somatic complaints. In contrast, the level of social strain accounted for a significant proportion of variance in depressive symptoms and somatic complaints 6 months later, but not quality of life. The results suggest that interpersonal relationships can be both positively and negatively associated with physical and mental health for people with ID.