Public authorities and academics have advocated for applying been advocating for the application of the settingbased approach to sports clubs. However, studies have shown that existing health promotion (HP) interventions in sports clubs poorly understand and apply this approach. Moreover, methods used to evaluate these interventions do not inform their implementation process, limiting the generation effectiveness' proofs. This study aims at evaluating the implementation process and effectiveness of an HP intervention in sports clubs (PROmotion de la Santé dans les ClubS de Spor; PROSCeSS), based on the health-promoting sports club (HPSC) model. A type 3 hybrid design, using a multiphase mixed-method: QUAN→QUAL→ QUAN+QUAL (qual)→QUAL (quan+qual), will be used. Phase A will be a pre-post-quantitative study with one HP officer, five managers and five coaches from 30 sports clubs exploring the effects of the PROSCeSS intervention on HP perceptions and health literacy. Phase B will be focus groups with participants from HP initiatives that the 30 sports clubs will have previously put in place to detect changes in health. Phase C will explain the results of phases A and B by choice of strategies and adherence to standardised steps, measured through semistructured interviews and implementation data collection. Phase D will cross-reference the semistructured interviews, the sports club characteristics questionnaire and the implementation data collection to study the relationships between the context and the implementation process. This protocol will identify 'what works', 'for whom', in 'what context' in terms of HPSC and clarify which intervention components are more effective at improving HP. This evaluation design will help to develop appropriate approaches to evaluate HP interventions. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY ⇒ This study represents a step in developing more generalisable HP interventions and implementation strategies for sports clubs.