Introduction: The population is quickly aging in Belgium and there is an increasing number of older frail adults. Occupational therapy (OT) in primary care (PC) favors the stay-at-home of frail older persons through its preventive action on the person, the environment, and/or the task. However, OT is not well implemented in Belgian PC. We aimed to investigate the implementation of OT, to support the frail older person living at home, within primary care in Belgium. Methods: We performed a secondary thematic analysis, based on data collected during an implementation study of an OT guideline for this population. Data were collected via four online focus groups, 16 individual online interviews, and a world café (N = 31 participants) which allowed us to triangle the data. The participants had various background and came from all the Belgian regions allowing us to benefit from a great range of opinions. Results: The analysis enables to identify barriers to OT implementation related to the financing system (e.g. significant lack of reimbursement in PC), the professionals’ knowledge (e.g. unknown OT roles and interventions), the communication (e.g. between professionals), and the territorial healthcare organization of the Belgian primary care (e.g. lack of PC structuration). But some facilitators also exist. Conclusion: OT is poorly implemented in primary care in Belgium, but with the aging population, the PC structuration and some display of valuable aspects of OT, it may be able to seize the opportunity to gain a firmer foothold in the Belgian PC.