BackgroundCulturally-appropriate family models of diabetes self-management education and support (DSMES) using community health workers (CHWs) have been shown to help address barriers to improving type 2 diabetes mellitus (T2DM) self-management for racial/ethnic minority communities; however, there is limited DSMES research among Marshallese and other Pacific Islanders. Using a community-based participatory research approach, we engaged community stakeholders to co-design a study to implement a culturally adapted family model DSMES (F-DSMES) intervention in faith-based organizations (FBOs) (i.e., churches). MethodsUsing a cluster-randomized controlled trial design, we will assess the effectiveness of the F-DSMES intervention for Marshallese patients with T2DM in Arkansas and Oklahoma. Twenty-four FBOs (with 12 primary participants per FBO) will be randomized to one of two study arms: the intervention arm or the wait-list control arm. Primary participants must have at least one family member willing to attend education sessions and data collection events. The F-DSMES intervention consists of ten h of diabetes education delivered by CHWs over eight to ten weeks. Data will be collected from the intervention arm at pre-intervention (baseline), immediate post-intervention (12 weeks), and three months post-intervention. The wait-list control arm will complete a second pre-intervention data collection before receiving the intervention. The primary study outcome will be glycemic control, as measured by HbA1c. Secondary measures include glucose, weight, body mass index, blood pressure, diabetes self-management behaviors, and diabetes management self-efficacy. ConclusionThe knowledge gained from this research will inform future DSMES and other health promotion interventions conducted with Marshallese and other Pacific Islander communities.