Adolescence is a period of changes, and it has been shown that participation in physical activity decreases during this stage. Personality may play a key role in this behavior; however, studies on this topic remain scarce. Objective: To establish the relationship between personality dimensions and physical activity in adolescents. Methodology: A cross-sectional study with 155 schoolchildren, evaluated using the PAQ-A questionnaire and the JS NEO-S inventory. Results were presented as means with standard deviation; t-tests were conducted to compare means by sex, and an adjusted linear regression model was performed. Results: The dimensions of responsibility (72.63) and openness to experience (71.03) had the highest scores; the average physical activity was 2.35 with differences by sex (p<.05). Conclusions: Physical activity was lower in women and was influenced by extraversion, responsibility, and openness to new experiences.