Public health interventions are complex in nature and composed of multiple components. Evaluation of process and impact is necessary to build evidence of effectiveness. Process evaluation involves monitoring extent of implementation and comparison against the program plan. This article describes the process evaluation of the ‘Qaderoon’ (We are Capable) intervention; a community-based mental health promotion intervention for children living in a Palestinian refugee camp of Beirut, Lebanon. The manuscript describes the context of Palestinian refugees in Lebanon, the intervention, the process evaluation plan and results. The process evaluation was guided by the literature and by a Community Youth Committee. Findings indicated that attendance was 54 and 38% for summer and fall sessions, respectively. Session objectives and activities were commonly achieved. Over 78.4% of activities were reported to be implemented fully as planned. Over 90% of the children indicated high satisfaction with the sessions. Contextual facilitators and challenges to implementing the intervention are discussed. The most challenging were maintaining attendance and the actual implementation of the process evaluation plan. Findings from process evaluation will strengthen interpretation of impact evaluation results.