Problem: Primary care providers are recognized as important advocates for physical activity (PA); yet, clinical PA discussions remain infrequent. Educational approaches promoting the uptake of strategies that are proven to increase patient PA levels are effective for improving primary care providers’ social cognitions and behavior for discussing PA with patients. However, research on the effectiveness of such educational interventions among family medicine residents is limited. Intervention : Using the Theory of Planned Behavior (TPB), an interactive, educational intervention was developed to increase PA discussion between first year family medicine residents and their patients. This study aimed to determine the impact of the intervention on residents’ social cognitions and behavior for discussing PA with all adult (18–64 years) patients. Context : The intervention condition was comprised of 15 first year residents (2017/2018) who: (1) received the full intervention, and (2) completed both the pre- and post-intervention TPB questionnaires assessing changes in PA discussion social cognitions, and (3) had their medical charts reviewed for PA discussion behavior. The nonintervention condition was comprised of 15 first-year residents (2016/2017) who were randomly selected to have their medical charts reviewed for PA discussion behavior. Impact : Although no significant differences in social cognitions were observed pre- vs. post-intervention, intervention condition residents’ perceptions of feeling adequately trained to discuss PA increased post-intervention (p = 0.005). A difference in residents’ PA discussion behavior was observed between conditions at post (p = 0.01), where PA was discussed at more patient visits among intervention condition residents. Lessons Learned : Findings suggest that the observed effect of resident PA discussion behavior being greater in the intervention condition at post may be attributed to the intervention condition residents having received the theory-based, educational workshops. This study highlights the importance of educating and training residents on strategies for PA discussion; however, future interventions should address both the reflective and automatic processing aspects of behavior and strive to influence organizational factors that impact resident behavior for discussing PA. Supplemental data for this article is available online at at 10.1080/10401334.2021.1891542