Psychosocial factors at work can affect individuals' physical and mental health. In this sense, evidence shows that physical activity and social support at work promote benefits to workers' health, especially regarding stress reduction. To evaluate the association between occupational stress, social support at work, and weekly frequency of physical activity among outsourced workers. This is a cross-sectional study with a convenience sample comprising 182 outsourced workers of both sexes and different positions, aged between 21 and 72 years (39 ± 11.4); the participants answered the Demand-Control-Support Questionnaire for assessing occupational stress and social support at work and the International Physical Activity Questionnaire - Short Form for assessing the frequency of physical activity. The association between constructs was investigated through a Poisson regression. The significance level was set to 5%. A significant inverse association (p < 0.05) was found between passive work and frequency of physical activity (walking) among women (relative risk 0.70; 95% confidence interval 0.5-0.9), whereas for men, this association was found with the frequency of vigorous-intensity physical activity (relative risk 0.70; 95% confidence interval 0.4-0.9). However, a significant inverse association (p < 0.05) between social support and physical activity was found only among women (relative risk 0.66; 95% confidence interval 0.4-0.9) and for moderate- and vigorous-intensity physical activity (relative risk 0.65; 95% confidence interval 0.4-0.9). Occupational stress and social support at work are associated with weekly frequency of physical activity. Nevertheless, disparities can be seen between men and women and depending on the intensity of physical activity.