Resumo. ABSTRACT Adolescence promotes biopsychosocial changes, such as increased independence and development of autonomy in making decisions about lifestyle practices and behaviors, as it may also influence lifestyle positively or negatively. Thus, the objective of the study was to analyze the effectiveness of health education interventions on the topics of healthy eating, physical activity and posture education in raising awareness of a healthier lifestyle in adolescents enrolled in two public schools in Criciuma, Santa Catarina. A prospective and analytical study was conducted in two state public schools, divided in two groups: Elementary School and High School. The sample consisted of 109 adolescents of both genders, aged 11 to 17 years. Questionnaires (pre and post action) were applied . Data was exported to SPSS version 20.0. The significance level α set for the statistical tests was ≤ 0.05 and a confidence interval was 95%. There was significant increase in knowledge about healthy eating (3,86±1,395/4,64±1,67), physical activity (4,52±1,696/5,10±1,46) and posture education (4,03±1,50/5,02±1,49). Regarding gender, both presented acquisition of knowledge. The actions carried out in schools have proven effectiveness in the acquisitionof knowledge by the students.