Objectives: This study aimed to examine the association between masticatory discomfort and subjective cognitive decline in Korean adults. Methods: We used data from the 2023 Korea National Health and Nutrition Examination Survey. A total of 5,340 adults aged 19 years or older were included in this study. Logistic regression analysis was performed to examine the risk of subjective cognitive decline according to masticatory discomfort after adjusting for sex, age, income, marital status, education, employment, drinking, depression, anxiety, and stress. Results: Participants with masticatory discomfort were approximately twice as likely to experience subjective cognitive decline as those without. After adjusting for sex, age, income, marital status, education, employment, drinking, depression, anxiety, and stress, participants with masticatory discomfort were approximately 1.3 times more likely to experience subjective cognitive decline. Conclusions: This study shows that masticatory discomfort is associated with subjective cognitive decline in Korean adults, suggesting that people with masticatory discomfort are at increased risk of cognitive decline.