Persons with dementia have the right to equal inclusion in rehabilitation, including physical activity. However, the perspectives of persons with dementia are rarely integrated into decision-making related to physical activity programming, services, and supports. Here, we describe the participatory action research (PAR) approach used to develop the Dementia-Inclusive Choices for Exercise (DICE) toolkit, which aims to increase the quality and number of physical activity opportunities available to persons with dementia. The DICE Research Team included persons with dementia, a family care partner, exercise professionals, community and dementia service providers, health care professionals, and researchers who worked to: 1) Engage/maintain the Research Team; 2) Set/navigate ways of engagement; 3) Understand barriers to physical activity; 4) Prioritize the audience and actions; 5) Develop the toolkit; 6) Conduct usability testing; and 7) Implement and evaluate. Guided by the Behaviour Change Wheel, and informed by interviews, focus groups, and existing research, our PAR Team chose to prioritize training exercise providers; exercise providers can enable exercise for persons with dementia if they understand common changes with dementia and how to support persons with dementia in exercise. The content and format of the toolkit was co-developed: drafted by our Research Team, adapted through a stakeholder workshop, and refined through iterative development and usability testing. The product of our PAR process, the DICE toolkit, includes videos meant to destigmatize dementia, training modules and a training manual for exercise providers, a physical activity handout for persons with dementia, and wallet cards to help persons with dementia communicate their abilities, needs, and preferences. Our usability study indicated that the toolkit could be used by exercise providers and may improve attitudes about dementia. Our vision is that our co-developed DICE toolkit will empower exercise providers to improve physical activity opportunities and support for persons with dementia.