Parents' are at risk for ictivity; however, research into understanding parental physical activity (PA) is scarce. We integrated self-determined motivation, planning, and theory of planned behavior (TPB) to understand better parental PA. Parents (252 mothers, 206 fathers) completed a main questionire assessing measures underpinning these constructs and a 1-week follow-up of PA behavior to examine whether self-determined motivation indirectly influenced intention via the TPB variables (i.e., attitude, subjective norm, and perceived behavioral control) and intention indirectly influenced behavior via planning. We found self-determined motivation on intention was fully mediated by the TPB variables and intention on behavior was partially mediated by the planning variables. In addition, slight differences in the model's paths between the sexes were revealed. The results illustrate the range of important determints of parental PA and provide support for the integrated model in explaining PA decision making as well as the importance of examining sex differences.