Background: Parkinson's disease (PD) is a movement disorder with no cure. Symptoms related to PD can be managed through physical activity (PA). However, individuals with PD tend to be sedentary. Purpose: The purpose of this study was to identify the perceived constraints and facilitators to PA in each stage of behavioral change for individuals with PD. Methods: A qualitative methodology was utilized to uncover factors influencing behavior from the participants' perspectives. Twelve participants were recruited and took part in a semistructured interview. Thematic analysis was performed on the data. Results: Constraints in the pre-intention stage related to psychological states. In the intention stage, interpersonal constraints resulted from participants' lack of support from others, and environmental constraints addressed accessibility. The action and maintenance stages saw a decrease in constraints. Few facilitators were mentioned in the pre-intention stage. The intention stage saw an increase in the variety of facilitators. Environmental facilitators in the intention stage highlighted the importance of accessibility to knowledge on programs. Facilitators were also important for maintenance of their PA behavior. Discussion: Findings suggest that multiple factors influence behavior at different stages of behavioral change in PA. Translation to Health Education Practice: These results can be utilized to develop/implement interventions to increase PA behavior in this population.