Background: Parent-adolescent conflict is complex and multifaceted construct as it includes any differences of opinions, whether it is negative or positive between parents. This study aimed to identify the parent-adolescents conflicts and its relation with their school achievement and self-esteem. A descriptive correlational research design was used. 1018 adolescents were recruited in this study. It was conducted at eight governmental preparatory schools, four schools in urban areas and four in rural areas in assiut governorate, Upper Egypt. Four tools were used for this study as demographic questionnaire for the adolescents and their parents, parent-adolescent issues checklist, adolescent self-esteem scale and adolescents' school achievement. Results indicated that the majority of the studied adolescents (93.6%) had conflict with their parents. The greater the conflict between adolescents and their parents, the higher the school achievements occurred, p=0.004. But there was no statistically significant relation between the adolescents' self-esteem and parent-adolescent conflict. Conclusion, the majority of adolescents had higher frequency of conflict issues but intensity of conflict was not severe with their parents. Parent-adolescent conflict had a positive effect on adolescent School achievement. The present study Recommended that, parents should be aware of physical, cognitive and psychosocial changes and needs of the adolescents to deal with their children positively. Periodical assessment should be done for self-esteem to all children in schools for early detection and management of any problem.