OBJECTIVE: Although family-based treatment (FBT) is considered a first-line treatment for adolescent anorexia nervosa (AN), it is underutilized in community settings and is unavailable to many families for a multitude of practical reasons (e.g., costs of treatment, transportation constraints). Adapting FBT interventions for delivery in home-based and community-based settings may reduce pragmatic barriers to treatment uptake and engagement. METHODS: This pilot effectiveness-implementation trial will assess outcomes, implementation, and mechanisms of FBT adapted for the home setting (FBT-HB), delivered in the context of community-based behavioral health agencies. Adolescents with AN-spectrum disorders (n = 50) and their caregivers will be randomly assigned to either FBT-HB or home-based treatment as usual (TAU; integrated family therapy approach). Caregivers and adolescents will provide data on weight, eating, and putative treatment mechanisms, including caregiver self-efficacy and adolescent eating-related and weight-related distress. Implementation constructs of feasibility, acceptability, and appropriateness will be measured among providers and participating families. HYPOTHESES: We expect that FBT-HB will be feasible, acceptable, and appropriate, and will outperform TAU in terms of improvements in adolescent weight and eating-related psychopathology. We further expect that caregiver self-efficacy and adolescent eating-related and weight-related distress, but not general distress, will show greater improvements in FBT-HB relative to TAU and will be associated with better adolescent weight and eating outcomes in FBT-HB. POTENTIAL IMPLICATIONS: The proposed study has clear potential to advance scientific and clinical understanding of the real-world effectiveness of FBT for AN, including whether adapting it for the home setting improves its accessibility and effects on treatment outcome.