High rates of dropping out from mental health services are documented for children and their families. These high rates exist at different treatment stages, in different service settings, and for different populations of children and families. Some researchers have developed and tested engagement interventions to address barriers to service access and use and increase participation in services by children and their families. Studies of engagement interventions for children and their families are critically reviewed in this paper. Overall, the engagement interventions were effective in increasing attendance at first appointments. Only those with an ecological and total service delivery approach reduced the drop-out rate. However, even then, the drop-out rate was 26% to 29%. Suggestions for future research are made, including ascertaining from children and families their reasons for quitting or staying in treatment, comparing the outcomes of drop-outs with the outcomes of those who remain in treatment, developing and testing conceptual models of engagement for subgroups of at-risk children and their families, and examining the cost-effectiveness of engagement interventions.