RESUMO
INTRODUCTION: the purpose of this study was to assess adolescents and teachers´ knowledge, attitude and practices towards family planning (FP). METHODS: in 2018, a qualitative study was conducted among seven teachers and 62 teenagers aged 15-19 years based on the Theory of Reasoned Action published by Fishbein and Ajzen in 2011. Data were collected from six focus group (FG) with adolescents and seven semi-structured interviews of teachers. They were analyzed using Atlas Ti software on the basis of a deductive approach. RESULTS: periodic abstinence, male condoms and pills were the only contraceptive methods reported. Adolescents and teachers were apprehensive about using artificial contraceptive methods other than irregularly used male condom. Girls prefer natural methods fearing side effects. The majority of adolescents wanted to be informed about FP in school; however, they felt that the content of the Life Education Course (EVIE) was insufficient and that teachers lacked of openness. Peers, brothers, sisters and internet were the main sources of information. Mothers were an important source of information especially for girls, unlike fathers who were generally less appreciated. CONCLUSION: knowledge about FP is weak. Misconceptions about contraception lead to the use of ineffective practices to prevent unintended pregnancies. Training programs to improve teachers´ knowledge should be developed and the content of the EVIE course should be formalized and regulated.