To analyse sex differences and associations regarding non-suicidal self-injury (NSSI) behaviour and their relationship with other health compromising behaviours. Were inquired 3262 Portuguese adolescents as participants in the context of the Health Behaviour in School-aged Children study/WHO. 20.3% of the adolescents reported at least one NSSI episode. Students from 8th grade had more NSSI than 10th grade students. Concerning sex, girls report more NSSI than boys. The occurrence of NSSI for both sexs is related to alcohol use, being bullied, being a bully, carrying weapons, and safety perception at school. Regarding boys, NSSI is also related to physical activity (PA), drugs use and school grade. For both sexs, being bullied, being a bully and carrying weapons had a positive association with the NSSI occurrence. For girls, also alcohol use had a positive association with the NSSI occurrence. Safety perception at school was negatively associated with the NSSI occurrence in girls. Regarding the 8th and 10th grade students’ being bullied and carrying weapons had a positive association with the NSSI occurrence. For the 8th grade students’ alcohol use and being a bully had also a positive association with the NSSI occurrence. Safety perception at school had a negative association with the NSSI occurrence for the 8th grade students. Specific strategies that address the NSSI occurrence in adolescents are needed for Portuguese adolescents and those needs presented age (grade) and sex specificities. Public policies must take these specificities on board while designing and implementing preventive interventions with families, in the school and in the community in order to promote a safer environment at school and adolescents’ positive development. These interventions will help adolescents to better self-regulate, seek social support, make better choices and to maintain a healthy lifestyle.

Aim: To analyse gender differences and associations regarding physical fights and their relationship with other health compromising behaviours. Methods: Participants consisted of 5,423 Portuguese adolescents in the context of the Health Behaviour in School-aged Children/World Health Organization study. Independent Chi-Square, Independent Sample T-tests were used to analyse the relationship between physical fights involvement and health compromising behaviour. Binary logistic regressions were conducted to analyse the associations between physical fights involvement and variables with statistical significance for at least one gender in preliminary bivariate analysis. Regression analyses were stratified by gender adjusted by age. Result: 21.3% of the adolescents reported at least one fighting episode. 61.1% of fights occurred in school. Students from 6th grade had a higher involvement in fights than 10th grade students. For both genders, fighting occurrence is related to consumptions (alcohol, drugs use), violence (being bullied, being a bully, carrying weapons and safety perception at school). Boys from Alentejo region, 6th grade and who practice physical activity, reported more physical fights involvement. For boys, carrying weapons decreases the probability of fights occurrence in school. Conclusion: This study confirms the impact of physical fighting in Portuguese adolescents and emphasizes that specific strategies to address this physical fighting are important. Public policies must take gender and age specificities into consideration while designing and implementing preventive interventions with pupils and families, in the school and in the community, in order to promote a safer environment at school and an adolescents’ positive development. Active social support from peers, parents, teachers and school staff is needed so that weapons are not used as a way to secure schools’ environment. National strategies and interventions in school context must be prioritized with regional focus in order to address regional specificities.