Background <p>Temporomandibular disorders (TMDs) are the most common non-dental orofacial pain conditions. Due to the potential elevated risk of TMD in bodybuilders and the lack of research in the Iranian population, this study aimed to investigate the prevalence and severity of TMDs and oral behaviors and compare associated variables among Iranian bodybuilders for the first time.</p> Methods <p>This cross-sectional study was conducted on 378 bodybuilders aged 18–60 years old who had been actively training for at least 6 months. The prevalence and severity of TMD were assessed using the Fonseca questionnaire, while oral parafunctional behaviors were evaluated using an Oral Behaviors Checklist (OBC). Ultimately, the study results were analyzed using the Chi-squared test, Fisher’s exact test, and Pearson correlation.</p> Results <p>The results of the Fonseca questionnaire showed that 48.2% of the participants have TMD. No significant relationship was found between the prevalence and severity of TMD and age, gender, months of bodybuilding, number of training hours per week, the heaviest weight used in the bench press, and Body Mass Index (BMI). According to the results of the OBC, 100.0% of the participants had oral parafunctional behaviors, and a significant relationship was observed between oral parafunctional behaviors and gender (<i>P</i> = 0.047) and the heaviest weight used in the bench press exercise (<i>P</i> = 0.002). According to the study, a significant correlation was observed between the prevalence of TMD and the prevalence of oral parafunctional behaviors (<i>P</i> = 0.02, <i>r</i> = 0.245).</p> Conclusion <p>About half of the bodybuilders have TMD, and all of them have oral parafunctional behaviors.</p>