Social support and psychiatric severity are known to influence substance abuse. However, little is known about how their influences vary under different conditions. We aimed to study how different types of social support were associated with substance abuse outcomes among persons with low and moderate psychiatric severity who entered Sober Living Houses (SLHs). Two hundred forty-five individuals entering 16 SLHs were interviewed at baseline and 6, 12 and 18 months. The Brief Symptom Inventory assessed psychiatric symptoms and the Important People Instrument and a modified AA Affiliation Scale assessed social support. Social support variables predicted substance abuse outcomes for persons with low and moderate psychiatric severity. However, they were the strongest and most consistent predictors for the low severity group.