Objective: To identify factors associated with physical activity engagement among adolescents in southeastern Spain. Methods: A cross-sectional study was conducted with a representative sample of 1817 adolescents from the Region of Murcia, using data from the 2018 HBSC Spain study. Two logistic regression models were analyzed. Model 1 included the full sample, with the dependent variable being compliance with the World Health Organization's physical activity recommendations (WHO-PAR), which include both moderate and vigorous physical activity. Model 2 focused on adolescents who did not meet the WHO-PAR but reported engaging in vigorous physical activity during leisure time at least four times per week. Results: In total, 19.7 % of adolescents met the WHO-PAR. Among those who did not, 24.8 % engaged frequently in vigorous physical activity (>= 4 times per week). In Model 1, being female (OR 0.43), older age (OR 0.87), and overweight/obesity (OR 0.59) were associated with lower odds of meeting the WHO-PAR. High family affluence (OR 1.71) and high perceived quality of life (OR 1.99) were associated with greater odds. In Model 2, being male (OR 1.94), high family affluence (OR 1.55), and high quality of life (OR 1.98) increased the likelihood of engaging in vigorous physical activity, while overweight/obesity (OR 0.61) decreased it. Conclusions: Not meeting the WHO physical activity recommendations and not engaging in vigorous activity were associated with low family affluence, being female, overweight/obesity, and low or medium perceived quality of life. These factors should be addressed in interventions to promote adolescent physical activity.