”Coping with Chronic Illness: A Systematic Review of Adaptive Strategies Across Cancer, COPD, Diabetes, and Heart Disease”. Abstract Background: Chronic diseases such as cancer, chronic obstructive pulmonary disease (COPD), diabetes, and coronary heart disease significantly affect individuals’ quality of life. These conditions require adaptive coping mechanisms to manage physical, emotional, and social challenges. This study contributes to public health literature by systematically reviewing and synthesising the coping strategies employed by individuals managing these chronic conditions. Objectives: The review aims to identify, categorise, and compare coping strategies employed by individuals with cancer, COPD, diabetes, and coronary heart disease. It also seeks to explore the personal, familial, and systemic factors that shape these adaptive responses. Methods: A systematic review of peer-reviewed studies published between January 2010 and September 2024 was conducted. Relevant articles were identified through PubMed, Scopus, and PsycINFO, using keywords such as ”chronic disease,” ”coping strategies,” ”cancer,” ”COPD,” ”diabetes,” and ”coronary heart disease.” Thematic analysis was used to synthesise the findings from selected studies. Results: Eight significant themes emerged from the review: maladaptive stress strategies, maintaining “normalcy,” medication use, emotional factors, expanding social networks, therapeutic interventions, complementary therapies, and the influence of religion/music/nature. These themes reflect the complexity and multidimensional nature of coping with chronic diseases. Problem-focused coping (e.g., self-management, goal-setting), emotion-focused coping (e.g., mindfulness, emotional support), and avoidance coping (e.g., denial, disengagement) were commonly employed strategies. Social determinants, including healthcare access, family dynamics, and community support, significantly influenced coping outcomes, with more substantial social support correlating with better psychological resilience and treatment adherence. Conclusion: Effective coping strategies for managing chronic diseases require a comprehensive approach that addresses individual coping mechanisms and the broader social and systemic influences. Interventions should focus on improving healthcare access, enhancing family and community support, and providing tailored psychological resources. Keywords: Chronic disease, coping strategies,