ICH is the evaluator for the SUSTAIN Communities, an initiative funded by the GE Foundation with support from Partners HealthCare. SUSTAIN Communities provides grants and technical assistance to community health centers to build capacity for Medication-Assisted Treatment (MAT) for patients with opioid use disorder. The program is run by the Massachusetts League of Community Health Centers. ICH is doing a mixed-methods evaluation to assess the impact of the program on staff and organizational capacity to provide MAT services. The evaluation utilizes a range of data collection approaches, including surveys, capacity assessments, interviews, focus groups, and grantee progress reports. Data collected through the evaluation have helped individual health centers identify gaps and areas of focus to optimize their programs, and have helped the grant managers and funder identify the areas of highest need for training and technical assistance offerings in the future.