Adolescence is a critical period of exposure to drugs and alcohol. Drug abuse among adolescents is increasing worldwide. The family is the primary source of influence during childhood and adolescence and plays a key role in the individual's decision to display risk behaviors. The sample in this study consisted of 30 couples, chosen from non-addicted parents of substance-abusing adolescents (12 to 18 years old) who had been referred to drug addiction treatment centers in the city of Bojnurd, northeastern Iran. These parents were compared with 30 couples from the control group, who were parents of non-addicted adolescents. Parents from both groups were matched one by one. The NEO Five-Factor Inventory (NEO-FFI) 60-item personality test and Jones’ (1968) Irrational Beliefs Test (IBT) were used as assessment tools in this study. Results showed that neuroticism was significantly higher in mothers of addicted adolescents whereas agreeableness, openness to experience, and conscientiousness was lower compared to mothers of non-addicted adolescents (p < 0.001). Neuroticism was significantly higher in fathers of addicted adolescents while they displayed lower openness to experience and conscientiousness. The overall score of illogical beliefs in mothers of addicted adolescents showed a significant difference with the control group, but this difference was not significant in fathers. Personality traits and irrational beliefs in parents influence their parenting style and lead to unreasonable expectations from adolescents, which can seriously impact onset of addiction in adolescents.