Objective. Our aim was to examine how the relations among known predictors of physical activity, such as age, sex, and body mass index, interact with future time perspective (FTP) and perceived functional limitation to explain adults’ engagement in physical activity. Method. Self-report data from 226 adults (range 20–88 years) were collected to examine the hypothesis that a more expansive FTP is associated with engagement in physical activity. Results. Results indicated a good fit of the data to the model χ2 (4, N = 226) = 7.457, p = .14 and accounted for a moderate amount of variance in adults’ physical activity (R 2 = 15.7). Specifically, results indicated that perceived functional limitation (β = −.140) and FTP (β = .162) were directly associated with physical activity. Age was indirectly associated with physical activity through its association with perceived functional limitation (β = −.264) and FTP (β = .541). Discussion. Results indicate that FTP may play an important role in explaining engagement in health promoting behaviors across the life span. Researchers should consider additional constructs and perhaps adopt socioemotional selectivity theory when explaining adults’ engagement in physical activity.