Given the unclear long-term effect and use of interventions for active ageing, it is urgent and important to understand the facilitators and barriers via co-design with older adults at the community level. First step of this project aims to lay the theoretical background and evidence base on developing toolkits for co-designing community-based behaviour change interventions with older adults. Rapid reviews were conducted in three disciplines to understand the effective behavioural change techniques for older adults, how to co-design with older adults on community-based interventions, and how to design tools for behaviour change that older adult can use. The outcomes are a list of effective behavioural change techniques for older adults; guidelines for co-designing older adults on community-based interventions; a checklist for developing user-friendly tools for designing behaviour change. These elements will serve as the foundation for developing the toolkit on co-designing with older adults for community-based behaviour change interventions. - The excel file BCTreview_open contains the details of the studies reviewed in the three rapid reviews