Background: Understanding the conceptual models that underpin interventions, and the linkage between mechanisms of action and their intended outcomes, makes replication possible. Aim: To identify and appraise conceptual models and mechanisms of action underpinning end-of-life care interventions to improve spiritual well-being. Design: A systematic review following the Preferred Reporting Items for Systematic Review and Meta-Analysis was conducted. Data sources: A comprehensive search was performed in eight databases from inception to January 12, 2021. Results: A logic model was developed and potential mechanisms of action were identified from the seven included studies. Conclusion: First, conceptual models that have relevance and appropriateness to cultural setting are required to underpin future intervention development and implementation. Second, careful intervention development should articulate the link between concept, mechanisms, and outcomes. Third, selection of valid outcome measured must have a strong justification of how the construct being measured relates to the intervention goals.