Objectives: This study aimed to investigate the relationship between oral health beliefs and oral health-related dietary behavior. Methods: The participants of this cross-sectional study were 728 middle school students living in Jeonju who were selected through convenience sampling. For the survey, self-administered questionnaires were completed in individual settings. The analysis model was the oral health belief model, and the analysis method was path analysis. Results: Among oral health beliefs, perceived susceptibility, perceived severity, perceived barriers, and self-efficacy were found to be correlated with the oral health-related dietary behavior index. Multiple regression analysis showed that factors affecting the oral health-related dietary behavior index were gender (female), perceived susceptibility, perceived severity, perceived barriers, and self-efficacy. Path analysis showed that variables that significantly impact the oral health-related dietary behavior index are perceived susceptibility, perceived benefits, perceived barriers, and likelihood of action. The factor with the greatest impact was perceived barrier; the lower the barrier, the higher the level of dietary behavior undertaken to prevent dental caries. Conclusions: Oral health beliefs are related to oral health-related dietary behavior. Since perceived barriers had the greatest correlation with oral health-related dietary behavior, measures must be taken to help remove the barriers.