© 2019 Nigerian Journal of Clinical Practice.Background: The aim of this study is to determine the relationship between healthy lifestyles behaviours and health-related quality of life (HRQOL) among Turkish school-going adolescents. Subjects and Methods: This cross-sectional study was conducted among 413 students studying in a secondary school of Istanbul, Turkey. Data were collected using a questionnaire containing socio-demographic characteristics, health promoting lifestyle behaviors and the Turkish generic health-related quality of life questionnaire for children (Kid-KINDL). Data were analyzed using descriptive statistics, t-test, Pearson's product-moment correlation, and a hierarchical multiple regression analysis. Results: Univariate statistics showed that gender, school grade, parental education level, monthly income, and all healthy lifestyles behaviours except for fruit and vegetable intake were associated with adolescents' HRQOL. Multivariate statistics indicated that participation in social activities and talking about their problems were the most important predictors of better HRQOL. Healthy lifestyles behaviours, especially talking about their problems to close friends and/or family members and participation in leisure-time social activity were related to better HRQOL of Turkish adolescents, independently of socio-demographic factors. Conclusion: Collaborative efforts among providers of school health and counseling services are urgently needed to improve all aspects of adolescent health.