Purpose
This scoping review aimed to identify the current state of the application of theories in research related to advance care planning and to analyze the types and characteristics of the theories applied. Methods: Using the scoping review methodology presented by Arksey & O'Malley, the articles published from 2010 to 2022 were searched by combining the terms "advance care planning," "theory," and "model" in five electronic databases; PubMed, CINAHL, EMBASE, KMBASE, and KISS. Results: Thirty-two studies were identified. Theory-based research has been actively conducted since 2019, with a total of 25 theories applied. Psychological theories were the most prevalent, accounting for 75.0% of the applications, followed by sociological theories (12.5%), public health theories (6.3%), and one nursing theory (3.1%). Theories were utilized to create a framework for data analysis, establish a philosophical underpinning, develop intervention frameworks, and derive new tools. Conclusion: Various theories have been applied to research on advance care planning, yet the application of nursing theory has been limited. To optimize end-of-life care and advance care planning from a nursing perspective, further research incorporating nursing theory is essential.