Adolescent substance use has become a serious concern nationwide. Although there are many ways of viewing adolescent substance use, family influence has been established as one of the strongest sources of risk and protection. A review of the literature indicated relevant theories for understanding adolescent substance use and specific family-based variables influencing adolescent substance use. In general, there seems to be a relationship between adolescent substance use and family-based risk and protective factors. Relevant theories identified in the literature review include family systems theory, social cognitive theory, social control theory, and strain theory. Specific family-based risk and protective factors include family relationships such as with siblings and parents and family characteristics such as ethnicity and religious backgrounds. Future implications for research and prevention/intervention in relation to family-based risk and protective factors are discussed.