Purpose <p>As people age, physical frailty often increases, and this can be worse in those who are obese. Changes in oral bacteria may also be associated with overall metabolic health. This study aimed to explore how selected salivary bacteria differ between obese and normal-weight older adults.</p> Methods <p>A total of 25 obese older adults and 25 normal-weight older adults were recruited for this study. Participants with a history of smoking, use of antibiotics or weight-loss medications, periodontitis, denture use, psychological disorders, or malignant tumors were excluded. Bacterial abundance was quantified using real-time quantitative PCR. Associations between bacterial abundance and fasting blood sugar (FBS), HbA1c, systolic and diastolic blood pressure, as well as anthropometric indices, were analyzed.</p> Results <p>The average age of the obese and normal-weight groups was 69.0 and 72.6 years, respectively. Among the assessed bacteria, the abundance of Bacteroidetes (<i>P</i> = 0.01) and <i>Veillonella</i> (<i>P</i> = 0.03) differed significantly between the two groups; however, these differences were no longer significant after adjustment for potential confounding factors. A significant positive correlation was observed between fasting blood sugar (FBS) and Actinobacteria (<i>r</i> = 0.32, <i>P</i> = 0.02) and <i>Gemella</i> (<i>r</i> = 0.30, <i>P</i> = 0.03). In addition, the abundance of Proteobacteria (<i>r</i> = 0.38, <i>P</i> = 0.006) showed a positive correlation with HbA1c.</p> Conclusions <p>Our findings suggest potential relationships between salivary microbiota and obesity-related clinical and metabolic characteristics in older adults.</p>