Introduction: Aging is associated with various changes in body tissues and organs, including the oral cavity, among older adults. A common oral problem among older adults is tooth loss. The number of teeth in older adults is related to nutritional status and cognitive function. Previous studies examining the relationship between the number of remaining teeth, nutritional status, and cognitive function among older adults have reported mixed findings. While some studies have identified an association among these variables, others have reported different results. These inconsistencies indicate that the relationship among these variables warrants further investigation. In this study, oral health was assessed based on the number of remaining teeth, while cognitive function was evaluated using the Mini-Cog and Clock Drawing Test. Therefore, this study aimed to analyze the correlation between oral health, nutritional status, and cognitive function among older adults. Methods: This analytical observational study employed a cross-sectional design and included 110 older adults aged ≥ 60 years with varying numbers of remaining teeth. Participants were selected using purposive sampling according to predefined inclusion and exclusion criteria. Participants underwent an intraoral examination to determine the number of remaining teeth. Nutritional status was assessed using the Mini Nutritional Assessment (MNA) Long Form and classified as good nutritional status, at risk of malnutrition, or malnourished. Cognitive function was assessed using the Mini-Cog and Clock Drawing Test and classified as normal cognitive function or cognitive impairment. Spearman's correlation test was used to analyze the correlation between the number of remaining teeth among older adults and nutritional status and cognitive function. Results: Among older adults with ≥ 20 remaining teeth, most had good nutritional status and normal cognitive function. The number of remaining teeth was significantly and positively correlated with nutritional status (Spearman’s ρ = 0.327, p < 0.001). A significant positive correlation was also observed between the number of remaining teeth and cognitive function (Spearman’s ρ = 0.534, p < 0.001). Conclusions: The number of remaining teeth was correlated with nutritional status and cognitive function among older adults.