Introduction. Physical education (PE) plays an important role in the acquisition of physical activity in leisure-time (PA) and sports habits (Kilpatrick et al., 2002). PE classes can improve adolescents' motivation to practice PA or sports outside of school and are an attractive field for analyzing PA related to variables such as behavioral intention (Sun and Chen, 2010). Self-determination theory (SDT; Deci and Ryan, 1985; Ryan and Deci, 2017) can help understand and explain human motivation and behavior. SDT also establishes that human behavior is motivated by the satisfaction of three primary and universal psychological needs (Ryan and Deci, 2000): relatedness, autonomy, and competence. Within the actual socialization practices relevant to BPN, interpersonal styles or behaviors that support said BPN are crucial. Our objective was to relate PE teacher interpersonal styles (support for autonomy, relatedness, and competence), motivation (autonomous, controlled, and amotivation), and the intention to engage in PA outside of school. Method. The participants were 655 students (317 boys, 335 girls) between the ages of 12 and 15 (M = 12.77; SD = 0.73), from both public and private secondary schools, who answered a set of questionnaires to measure the study variables. Results. Students' perception that their teacher supports each of the BPNs is positively associated with autonomous motivation in PE clases and the intention to engage in physical activity outside of school, as well as negatively with amotivation. Amotivation is negatively associated with the intention to engage in PA. Conclusion. A PE teacher showing support for BPNs is associated with a greater intention to engage in PA outside of school in adolescents immersed in PE.