Sons of substance‐abusing (SA+) fathers and sons of control (SA‐) fathers were compared on measures of parental discipline, temperament, and problem behavior. It was found that discipline was less effective in 10–12‐year‐old boys of SA+ parents compared with boys of SA‐ parents. Children in the SA+ group also scored higher on the constellation of traits comprising a difficult temperament. In the SA+ group only, parental discipline explained a significant, albeit modest, amount of variance on the Child Behavior Checklist summary scores measuring the externalizing and internalizing behavior of the boys. Temperament did not exercise a moderating influence on the association between parental discipline a