How can orchestra teachers diversify curricula to engage young musicians in project-based learning experiences that build their musicianship and confidence? This action research study explores how the author fostered project-based learning experiences that incorporated student reflection and assessment within chamber music ensembles. By incorporating opportunities for students to build skills through chamber music ensembles, music teachers can foster students' engagement, develop students' confidence, and improve large-ensemble performances. Included as well are recommendations for implementing a chamber music unit that incorporates structured student reflections and authentic assessment.