Purpose: This study sought to advance the state of knowledge regarding physical activity and aging by identifying areas of agreement among experts regarding topics that are well understood versus those that are in urgent need of continued research efforts. Design and methods: We used a web-based survey with snowball sampling to identify 348 experts who were invited to complete a brief web-based survey. Responses were received from 38% of invited respondents. Results: Respondents reported that the efficacy and effectiveness of several types of physical activity were well understood but the dose–response relationship required for a health benefit was not. In general, more research is needed examining the effectiveness of programs on cognitive health outcomes and the impact of multiple risk factor programs. With respect to translation, more research is needed on how to maintain older adults in evidence-based programs and how to adapt programs for special populations. Researchers agreed that racial/ethnic minorities; persons with low socioeconomic status; and those with physical, intellectual, or mental health disability were substantially understudied. Finally, research on maintenance, implementation, and reach with respect to these populations was judged to be more urgently needed than research on efficacy and effectiveness. Implications: A substantial amount of consensus was found across a national group of experts. These findings should be instrumental in forging a new research agenda in the area of aging and physical activity.