Grounded on the Reflective–Impulsive Model, a recent study by Cheval, Sarrazin, Isoard-Gautheur, Radel, and Friese (2015) found support for an interactive pattern between reflective (i.e., physical activity intentions) and impulsive (i.e., impulsive approach tendencies towards sedentary behaviors; IASB) processes to prospectively predict objective moderate to vigorous physical activity (MVPA) — strong IASB hindered reflective intentions from being executed. As low self-control is presumed to be associated with the stronger influence of impulsive processes on behavior, the present article provides a secondary analysis testing whether the interactive pattern between reflective intentions and IASBmay bemoderated by different facets of self-control (i.e., restraint and impulsivity). Ninety-seven adults completed a questionnaire assessing the study's variables of interest andwore an accelerometer over one week. Results revealed a moderated moderation pattern between intentions, IASB, and trait impulsivity — the previously documented interactive effect between intentions and IASB on objective MVPAwasmore pronounced for individualswith high as compared to lowtrait impulsivity. The results underline the dynamic interplay between intentions, IASB, and self-control in the determination of physical activity behavior.