Background <p>The increasing trend of senior citizens and their complex healthcare needs demands the improvised provision of healthcare services and strategies to improve health service utilization to ensure health for all. Although health service provision has been prioritized, health service utilization is also a prime aspect that should be addressed to target the chronic needs of senior citizens. This study aims to assess the status of health service utilization and its influencing factors among senior citizens in rural municipalities of the Kaski district, Nepal.</p> Methods <p>A cross-sectional study was carried out in selected wards of all rural municipalities of Kaski District (Annapurna, Machhapuchre, Madi and Rupa). The study included a sample size of 392 senior citizens. Data were collected using a semi-structured interview schedule based on the Andersen‒Newman behavioral model using the Study on Global Aging and Adult Health (SAGE) questionnaire to assess health service utilization. Data analysis included descriptive statistics to summarize participant characteristics and health service utilization patterns. Additionally, bivariate and multivariable logistic regression analyses were performed to identify key determinants of healthcare utilization, adjusting for potential confounders. All statistical analyses were conducted using Statistical Package for Social Sciences version 20, with a significance threshold set at <i>p</i> &lt; 0.05.</p> Results <p>More than half (54.6%) of the senior citizens in the study visited healthcare facilities in the 12 months. Health service utilization was significantly associated with awareness of free healthcare services, membership in social health insurance, family support, self–perceived health status, independence in activities of daily living, and having a chronic disease with a p-value less than 0.05 and 95% confidence interval. After controlling for confounders, membership in social health insurance (aOR = 3.85, 95% CI: 2.31–6.40, <i>p</i> &lt; 0.001), family support (aOR = 2.06, 95% CI: 1.01–4.15, <i>p</i> &lt; 0.05), and the presence of chronic disease (aOR = 2.92, 95% CI: 1.70–4.98, <i>p</i> &lt; 0.001) were statistically significant with health service utilization among the senior citizens.</p> Conclusions <p>Many senior citizens did not utilize the healthcare services. Enrollment in social health insurance, awareness of free health services, family support and presence of chronic conditions were significantly associated with higher health service utilization. This suggests that to increase health service utilization awareness about health, including social health insurance, and fostering a sense of security and well-being is crucial.</p>