Aim: To analyze the association of social and personal influence on the practice of physical activity according to gender and age in high school students of the commune of Talca-Chile. Methods: Cross-sectional quantitative study, 744 schoolchildren (X=15.11 years; 459 males (28.81%) and 285 females (15.22%)). The IPAQ and the questionnaire of influences on Physical Activity and Health were applied. Results: Men are more influenced by parents in the motivations and social support to talk and do physical activity (61.4%) and in women, the influence is greater from school. Personal interest is the most relevant influence at the level of motivation; however, it is also recognized as one of the negative influences on physical activity. The reasons for low regular physical activity are lack of free time, personal interest and lack of motivation. Conclusion: Gender is associated with personal and social influence to practice physical activity, and age is inversely associated with social influence to talk, number of times of physical activity with friends and reasons for not doing physical activity.