Background: Although older adults with intellectual and/or developmental disabilities face high risks of maltreatment, there are few interventions available to reduce these risks. This study describes the development of a research-based intervention that aims to reduce the risks of maltreatment for this population. Method: The development involved close collaboration with a program advisory board (PAB). It used a three-phase approach with a cross-cultural perspective: (1) performing a needs assessment, (2) determining content and design, and (3) evaluating the usability of the intervention. Results: The needs assessment results and input from the PAB yielded critical information that helped shape the intervention's development. Feedback from the trainers confirmed the intervention's usefulness and revealed suggestions for enhancing its usability. Conclusions: The intervention developed appears to be promising for enhancing the knowledge and skills of older populations to reduce their exposure to maltreatment risks; future research should be conducted to assess its efficacy.