Purpose: To evaluate the association between attention-deficit/hyperactivity disorder (ADHD) symptoms reported by parents and the variables sleep problems, possible sleep bruxism, possible awake bruxism and dental trauma (DT), and its mode of occurrence in children and adolescents.<br/> Methods: A cross-sectional study was conducted with the parents of 144 four- to 16-year-old subjects through a questionnaire on demographics, subjects' sleep, self-reported bruxism and DT mode of occurrence. The Swanson, Nolan and Pelham scale IV was used to assess ADHD signs and subtypes. Bivariate and multivariate analysis were performed (P <0.05).<br/> Results: The subjects' mean age was 7.9 years (±2.8 years) and 50.7 percent were boys. DT was reported in 80 percent of those with the hyperactive/impulsive subtype (ADHD-HI) and 72.7 percent of those with the combined subtype (ADHD-C). DT was caused solely by falls in the ADHD-C and inattention subtypes (ADHD-I). ADHD-C was associated with somniloquy (prevalence ratio [PR]=1.075; P =0.010). ADHD-HI was associated with bad sleep quality (PR=1.194; P =0.005), possible sleep bruxism (PR=1.088, 95% confidence interval=1.006 to 1.176; P =0.034), possible awake bruxism (PR=1.146; P =0.024) and sleep duration (PR=0.88; P =0.02).<br/> Conclusion: ADHD-C and -HI subtypes were associated with sleep characteristics. Possible sleep and awake bruxism were associated with symptoms of ADHD-HI. Despite no significant association, DT was present in most ADHD subjects, mostly due to falls.