This chapter outlines the methodological framework of the Hellenic Relay study, a multi-year, community-based action research project commissioned by the Hellenic Heritage Foundation to investigate the state of Greek heritage language (HL) education in Canada. Situated within a Community-Based Action Research (CBAR) paradigm, the study prioritizes collaborative engagement with stakeholders and aims to produce knowledge that is both academically rigorous and socially actionable. Against the backdrop of a heritage language ecosystem shaped by historical continuity yet challenged by shifting demographics, declining enrollments, and increased competition from mainstream and global language programs, this study responds to urgent calls for renewal and innovation in HL education. The chapter articulates the research questions, describes the theoretical and methodological foundations, and outlines participant recruitment strategies, data collection tools, and analytical procedures. Ethical considerations, validity, reliability, and researcher reflexivity are also addressed. As both a methodological account and a resource for scholars and practitioners, the chapter contributes to the broader objective of the volume: to advance evidence-informed, community-responsive research in multilingual and diasporic language education contexts.