Background <p>Loneliness and social isolation among older adults is a growing concern in many societies, as the aging population continues to increase. The aim of the study is to examine the relationship between loneliness and quality of life in individuals aged 65 and over who apply to primary health care institutions.</p> Methods <p>This descriptive-correlational study was conducted face-to-face with 216 individuals aged 65 and over. The socio-demographic form and the Loneliness Scale for Elderly and Quality of Life Scale were used as data collection tools in the study. JASP 0.19, SPSS 26 analysis programs were used to perform t test, One Way ANOVA Bonferrroni test, Pearson correlation, and regression analysis.</p> Results <p>According to Pearson correlation analysis, strong negative relationships were found between quality of life and loneliness in the elderly. As quality of life increased, levels of loneliness, social loneliness, and emotional loneliness decreased (<i>r </i>= −0.854, <i>r </i>= −0.737, <i>r </i>= −0.717; <i>p </i>&lt;0.001). While there was a strong positive relationship between the loneliness scale for elderly and the social loneliness sub-dimension (<i>r</i> = 0.867, <i>p</i> &lt; 0.001), there was also a positive relationship between the loneliness scale for elderly and the emotional loneliness sub-dimension (<i>r</i> = 0.835, <i>p</i> &lt; 0.001). A statistically significant difference was found between chronic disease, educational status, income status, marital status, and both loneliness and quality of life.</p> Conclusion <p>Loneliness is an important predictor of quality of life among older adults. Both social and emotional loneliness are negatively associated with quality of life, indicating that higher levels of loneliness are linked to lower quality of life in this population.</p>