Parent-teen conflict has been associated with both acting-out behaviours and psychiatric disorders in adolescence, which indicates serious conflicts have negative sequelae that goes beyond the specific area of disagreement. The efficacy of traditional cognitive-behavioural interventions focusing on communication and problem-solving training has been demonstrated, but limitations have been recognised. One possible reason might be a lack of understanding the origin or underlying cause of conflicts in terms of adolescent social-cognitive development. The initial study utilised a package of self-report measures to investigate actual conflict levels in New Zealand families, and factors suggested as relating to conflict. Measures were completed by 112 parent-teen dyads. Results indicated high levels of conflict were occurring over everyday issues such as doing chores, tidy bedroom, swearing, going out, and homework. Also, higher conflict levels were associated with authoritarian parenting behaviours, lower perceptions of the parent-adolescent relationship, and poorer psychological well-being, but not with divergent conceptions of who makes decisions regarding adolescent behaviour. Main findings from the survey study were that parents and teens categorised issues differently according to four social-cognitive domains: moral, conventional, prudential (safety) and personal. Parents generally treated issues as belonging to safety and moral domains, while teens categorised issues more often as belonging to the personal domain. Discrepant categorisation of issues to domain categories was related to higher frequency and anger-intensity levels of discussions, supporting the hypothesis that parent-adolescent conflict can be meaningfully understood within a social-cognitive framework. To investigate whether these constructs could be used in cognitive-behavioural treatment, an exploratory treatment study was designed that compared providing a strategy to assist teens and parents articulate and justify their reasoning in the context of social-cognitive domains with the standard cognitive-behavioural problem solving intervention. Thirty-two self-referred parent-adolescent dyads reporting high conflict levels and negative family environments were randomly assigned to either the Domain and Development group or the Problem Solving group. Treatment duration was approximately 6 weeks. Dyads were seen individually. Results showed a similar general trend of improvement for parents and teens in both treatment groups, with a large percentage of individuals reporting meaningful changes after each treatment. Differences that did emerge tended to favour parents in the Problem Solving group and teens in the Domain and Development group, but variable response to treatment appeared more attributable to individual family circumstances than to each intervention. Statistical comparisons did not reveal differences according to teen age or gender, parent gender, religious affiliation, family composition, or dyad. Treatment evaluations, however, generally indicated that middle adolescents were more responsive to the Domain approach and rated it as more acceptable than did early adolescents. Overall, this project has demonstrated that greater mutual understanding of fundamental differences between parents and teens that lead to conflict, rather than focusing on problem-focused strategies that address conflictual topics only, can reduce their conflict levels. Findings are discussed within the context of theoretical principals guiding treatment outcome research, and recommendations regarding combining the two approaches in clinical practice are made.