The increasing prevalence of chronic illnesses among the elderly affects their physical and psychological well-being, contributing to emotional burdens and feelings of burdensomeness. This study aims to investigate the mediating and moderating role of social support in the relationship between psychological well-being and burdensomeness among elderly individuals with chronic illnesses. A cross-sectional descriptive design was employed, involving 311 participants aged 60 and older, recruited through purposive sampling. Data were collected using validated instruments via structured interviews conducted from June to August 2024. The results indicate that perceived burdensomeness has a strong negative effect on psychological well-being (r = -0.654). Social support significantly mediates this relationship, with higher social support associated with lower burdensomeness (β = -0.646) and improved psychological well-being (β = 0.318). Strengthening social support networks can mitigate feelings of burdensomeness and promote mental health, ultimately enhancing the quality of life for older adults facing chronic health challenges.