Objectives: Health-promoting behaviors are essential for maintaining independence and enhancing quality of life in aging populations. This study aimed to investigate the relationship between social support and health-promoting behaviors among older adults in Fasa, Iran in 2020. Methods: A cross-sectional study was conducted involving 300 older adults attending a specialized outpatient clinic in Fasa, Iran. Data were collected using a demographic questionnaire, the Walker Health-Promoting Lifestyle Profile, and the Canty Perceived Social Support Scale, administered either through self-report or structured interviews. Statistical analyses were performed using SPSS version 25 and included descriptive statistics, analysis of variance, the chi-square test, and multiple linear regression analyses. Results: The mean age of participants was 68.9±7.8 years. Most participants were women (56.6%), married (81.7%), and had less than a high school education (41.3%). The mean scores for health-promoting behaviors and perceived social support were 124.2±31.3 and 24.4±9.4, respectively. A statistically significant positive association was observed between perceived social support and health-promoting behaviors (r=0.10, p=0.04). Social support, gender, and education level were identified as significant predictors of health-promoting behaviors, collectively explaining 34% of the variance. Conclusions These findings emphasize the pivotal role of social support in promoting health-related behaviors among older adults. Interventions that strengthen social support networks, foster enabling environments, and address gender and educational disparities are recommended to improve health outcomes and quality of life in aging populations. Policymakers and healthcare planners should incorporate these determinants into the design of targeted, evidence-based interventions for older adults.