Background and Objectives: Positive Youth Development (PYD) is a strength–, based construct of development that can be defined as engaging in pro–, social behaviors and avoiding Health–, compromising behaviors and future jeopardizing behaviors. Contrary to other views, PYD does not consider adolescence as a turbulent and dangerous stage and should be managed,rather, it addresses this period as the source of fundamental changes and catches for the individual. Instead of focusing on adolescence deficits and the potential for risks and crises, such as stress, anger, etc., PYD focuses on adolescents' strengths and abilities,therefore, considering the large population of adolescents in Iran and the critical role of the family and its structure in preventing crises and the emergence of problems for adolescents, comprehensively examining the family structure and its role in adolescent development is essential. Therefore, this study aimed at investigating the relationship between Family Structures (FSs) and PYD. Methods: This was a descriptive and correlational study. The statistical population consisted of all students aged 11 to 18 years from sixth to twelfth grades in Tehran City, Iran, in 2016–, 2017 who were selected using the multistage cluster sampling method (N=300,137 girls & 163 boys) with a mean±, SD age of 15. 59±, 1. 67 years. Accordingly, the research objectives and the subjects' expectations were discussed. The questionnaires were administered in a quiet room away from disturbing visual–, auditory stimuli in schools and individually by the researcher and a research assistant. The study lasted two months. Research tools included the Family Adaptability and Cohesion Evaluation Scale (FACES IV,Olson et al., 2006) and Positive Youth Development Scale (PYDS,Geldhof et al., 2014). Research data were analyzed by descriptive statistics (frequency, mean, SD) and inferential statistics (Pearson correlation coefficient & multivariate linear regression analysis) in SPSS at the significance level of 0. 05. Results: The obtained findings suggested a positive and significant relationship between competence with family cohesion (r=0. 32, p=0. 04), flexibility (r=0. 33, p=0. 02), family satisfaction (r=0. 21, p=0. 04(, and family communication (r=0. 33, p=0. 03). There was a negative and significant relationship between competence and enmeshed style (r=–, 0. 21, p=0. 04) and chaotic style (r=–, 0. 22, p=0. 03). There were positive and significant relationships between connection with family cohesion (r=0. 35, p=0. 03), flexibility (r=0. 38, p=0. 02), family satisfaction (r=0. 35, p=0. 03), and family communication (r=0. 33, p=0. 03). There was a negative and significant relationship between the connection with enmeshed styles (r=–, 0. 24, p=0. 04), chaotic (r=–, 0. 19, p=0. 03) and rigid (r=–, 0. 16, p=0. 04) aspects. Furthermore, there was a positive and significant relationship between a character with family cohesion (r=0. 30, p=0. 04) and flexibility (r=0. 31, p=0. 04). There were negative and significant relationships between the dimension of character with enmeshed styles (r=–, 0. 23, p=0. 04), chaotic (r=–, 0. 23, p=0. 03), Rigid (r=–, 0. 19, p=0. 04) and communication (r=–, 0. 14, p=0. 04). Moreover, there was a positive and significant relationship between care and family cohesion (r=0. 14, p=0. 04), flexibility (r=0. 27, p=0. 03), and family satisfaction (r=0. 26, p=0. 03). There was a negative and significant relationship between care with enmeshed (r=–, 0. 26, p=0. 03), chaotic (r=–, 0. 14, p=0. 04), and relationship (r=–, 0. 22, p=0. 04). There was no significant relationship between the confidence dimension in the positive youth development and any family styles. According to the stepwise regression analysis data, among the family styles, two balanced cohesion and chaotic styles, altogether, accounted for 16% of the change in the competence dimension. In sum, balanced flexibility and family satisfaction styles predicted and explained 19% of the variance connection dimension. Family satisfaction and chaos altogether accounted for 13% of the changes in the character dimension, and the family relationship accounted for 7% of the changes in the caring dimension. Conclusion: The present study findings suggested a significant relationship between FS and PYD. Thus, these findings can effectively design and facilitate studying educational protocols to reduce problems and prevent crises in Iranian adolescents and families.