Lynch syndrome (LS) is the most common inherited cause of colorectal cancer. Although testing all colorectal tumors for LS is recommended, the uptake of reflex-testing programs within health systems has been limited. This multipronged study describes the design of a provincial program for reflex testing in Ontario, Canada. We recruited key stakeholders to participate in qualitative interviews to explore the barriers and facilitators to the implementation of a reflex-testing program. Data were analyzed in an iterative manner, key themes identified, and a framework for a proposed program developed. Twenty-six key informants participated in our interviews, and several themes were identified. These included providing education for stakeholders (patients, primary care providers, surgeons); challenges with sustaining various resources (laboratory costs, increased workload for pathologists); ensuring consistency of reporting test results; and developing a plan to measure program success. Using these themes, a framework for the reflex-testing program was developed. At a subsequent stakeholder meeting, the framework was refined, and recommendations were identified. This study identifies factors to ensure the effective implementation of a population-level program for reflex LS testing. The final product is a prototype that can be utilized in other jurisdictions, taking into account local environmental considerations.