Objectives: This study aimed to determine the level of physical activity (PA) based on gender, age, and states of change of adolescent students, as well as assess PA during free time, physical education classes, and weekends using validated questionnaires. Methodology: The study was non-experimental and cross-sectional, with a descriptive scope and a quantitative approach. The population was 1550 students, and a sample of 624 adolescents was considered, of which 309 were women and 315 were men, enrolled at "Bernardo Valdivieso" High School in Loja-Ecuador, through non-probabilistic convenience sampling. The physical activity levels were measured through the IPAQ-A condensed version questionnaire and states of change with the transtheoretical model of physical exercise change questionnaire that places people in 5 stages (pre-contemplation, contemplation, preparation, action, and maintenance). Results: Among the results, it stands out that the PA level of the population is low (M = 2.36), with women being less active than men. Conclusions: Likewise, it was determined that 60.57% of the population is in stages of change that are not continually active, with the highest percentage of adolescents in the contemplation stage.