Purpose: The relationship between sleep bruxism (SB) and temporomandibular disorders (TMD) is unclear. This study aimed to estimate SB prevalence in an adolescent population and to investigate the relationship between SB frequency and prevalence of TMD signs/symptoms. Materials and Methods: First-year students at a high school in Okayama, Japan, were recruited in 2005, with 195 subjects responding. The SB detection device was a miniature disposable device (BiteStrip, SLP) that indicated the total SB events per night on a 4-grade score. The subjects were divided into severe and nonsevere SB groups with SB frequency cutoffs. The subjects were examined for temporomandibular joint (TMJ) noise during mouth opening/closing, tenderness of the masticatory/cervical muscles, and range of TMJ condylar movement. The presence/absence of headache and shoulder stiffness was also determined by the interview. The odds ratio (OR) and confidence interval (CI) were calculated to test the relationship between SB frequency, gender difference, and presence of the TMD signs/symptoms by multiple regression analysis. Results: Severe SB (more than 125 events per night) was significantly related to the presence of TMJ clicking (OR: 3.74, CI: 1.22-11.49, P = .02), while gender (male) was not related to the presence of TMJ clicking. Severe SB was not related to headache, though gender (male) was significantly related to headache (OR: 2.52, CI: 1.04-6.11, P = .04) in these subjects. Conclusion: These results suggest that the presence of TMJ clicking was closely related to severe SB in an adolescent population.