The purpose of this research was to identify those dimensions of the Internal Implementation Context that facilitated or hindered the implementation of a community-based public school mental health (SMH) program. Fifty-one members of the educational communities in which the program is implemented were interviewed. The semi-structured interviews were analyzed using quantitative and qualitative content analysis. The results made it possible to (1) identify three main categories: organizational scenario, information management and organizational receptivity, which accounted for the main contents highlighted by those participating in the program and (2) establish, according to the positive or negative evaluation given, those dimensions operated as facilitators or hinderers in the implementation of the program, which were pointed out as central and critical aspects to understand the performance and effectiveness of the program studied. Implications, limitations and projections of the findings are discussed.