Juvenile delinquency is one of the most important social issues in Iran as it may lead to other social problems throughout adulthood such as murder, violence, aggression, and so on. One of the well-known causal factors of juvenile delinquency is association with delinquent peers. Present paper aims to study the relationship between juvenile companionship with parenting styles. This is a descriptive, cross-sectional study in which hypotheses were tested via correlation. The target population consisted of 14-19 years old students in Tehran in 1393, among them 384 students were selected using multistage cluster sampling method. Reliability and validity of research instrument were calculated using Cronbach's alpha and exploratory factor analysis. Results indicated that authoritative and permissive parenting styles explained 40/3% of the variance in drug and alcohol use and 31.7% of the tendency toward conflict. Finally, Authoritarian style of parenting had no significant relationship with delinquent peers’ companionship, while authoritative and permissive styles, respectively, were risk and protective factors for this kind of association.