Many people experience struggles in religious and spiritual (r/s) life, struggles that can reflect deep questions and conflicts regarding core beliefs about God, the world, and existence. Over the past 15 years, studies have shown that many people experience r/s struggles and that such struggles are linked with indicators of distress and poor health, including higher mortality rates. Yet some studies also suggest that struggles may be tied to growth and transformation. These studies have piqued professional and public interest in the topic of r/s struggle, which is now poised just at the edge of the mainstream. A narrow focus on linking r/s struggle with distress (often via cross-sectional studies) has left 2 key questions unanswered: 1) What factors reduce or increase vulnerability to the development of struggles? 2) What factors predict the trajectories and outcomes of struggle? Three longitudinal studies are proposed. The first study, which will identify predictors and temporal patterns of struggle, will examine undergraduates over their college years. The second and third studies will both focus on trajectories, coping responses, and outcomes of struggle within a broad-based adult sample (Study 2) and within a clinical sample of veterans recently returned from war (Study 3). Smaller-scale opportunity studies will also be conducted to examine more specific struggle-related topics (e.g., struggles in specific religious groups; religious doubt, demonic or divine struggles, anger at organized religion). The project will also integrate, disseminate, and stimulate literature on struggle through the generation of a scholarly book and review paper. These integrative projects, combined with the new data collection and associated publications in high-impact journals, will greatly strengthen the empirical and conceptual foundation for r/s struggle research and set the stage for future empirical and applied work involving larger teams of researchers and practitioners.