Implementation of evidence-based assessment and intervention approaches for youth with behavioral and/or emotional problems is rising to recognition worldwide. Feasibility research is critical to examine what characteristics of systems allow for success or barriers to the implementation of evidence-based practices into real-world settings, especially when working cross-culturally. This paper briefly reviews the experience of 4 international sites to understand how the overall structure and specific site variables directed the implementation of the World Health Organization and the World Psychiatry Association project. Discussion includes a thematic summary of the successes and challenges experienced by the sites, and future directions of feasibility studies.