This chapter examines advance care planning (ACP) in Japan through a sociocultural lens, highlighting how perceptions of life and death, family relationships, religion, and historical norms shape end-of-life decision-making. It first outlines the sociocultural background influencing Japanese views on mortality, followed by an exploration of family-centered healthcare traditions that prioritize collective harmony over individual autonomy. The chapter then discusses the nuanced role of religion in Japan, where spiritual practices often coexist with largely secular attitudes towards death. Against this backdrop, ACP is defined within the Japanese context, tracing its policy development and implementation to date. Comparative perspectives with other Asia–Pacific countries are presented to clarify both distinctive and shared regional features. The chapter also addresses appropriate timing for ACP discussions, ethical challenges, and communication barriers faced by patients, families, and healthcare professionals. Finally, it proposes culturally sensitive ACP models and considers policy- and system-level implications to support meaningful, context-appropriate end-of-life planning in Japan.