Objective This article aims at filling some gaps in the literature regarding conditions conducive to high-quality collaborative care in youth mental health (YMH) for migrant families. It focuses on the factors that are susceptible to foster the engagement of migrant families in the services, by examining the clinical encounter, as well as sociopolitical and institutional dimensions. Methods Using a multiphase mixed methods design, it sequentially follows qualitative and quantitative results regarding migrant families within the different projects of a research program on collaborative care in YMH in culturally and socioeconomically diverse neighborhoods, done in Montreal during the last decade. These results come from data collected through questionnaires, semi-structured interviews, focus groups, participatory observation and documentation, with research participants being children, adolescents and parents from migrant families, clinicians and managers. Results The results suggest that the sociopolitical and macro institutional system finds its way into the clinical space by influencing the process of care. In particular, successive reforms of the health system challenge institutions and YMH teams in their capacity to create a favourable environment for continuity of care and interinstitutional partnership and interprofessional collaboration, factors associated with families' engagement into care. This engagement is also dependent on the representations of mental health and services that migrant families hold. These representations are shaped by their experience of the services, but also by what their sociocultural environment and the public discourses allow them to imagine of these services. This calls for the integration of cultural and sociopolitical dimensions within the concept of engagement. Finally, results also suggest that schools are playing an important role to foster engagement in mental health care. Conclusion The quality of mental health care for migrant children and adolescent relies on the engagement of families, as well as on the mutual engagement of clinicians and of their institutions. Political contexts where tensions between majority and minority groups are present can also act as barriers to the care. Given that migrant families are engaging less in the services compared to non-migrant families, these considerations call for an important review of avenues to facilitate engagement of migrant families into collaborative care YMH services. This article suggests certain avenues to promote this engagement.