BackgroundClinically, data on the association of early‐life secondhand smoke (SHS) exposure with sleep bruxism and dental problems are scarce.ObjectiveTo examine whether the relationship between early‐life SHS exposure with sleep problems, sleep bruxism, and dental problems in children.MethodsWithin the scope of this study, questionnaires were applied to the volunteer parents of 710 children, aged 5–12 years old. The questionnaire applied in this study named as Children's Sleep Habits Questionnaire (CSHQ) and consists of seven subscales and a total of 33 items. The questionnaire was completed retrospectively by any parent, and the presence of sleep bruxism was questioned during the anamnesis. Afterward, the presence of dental decay and tooth wear was evaluated during intraoral and radiographic examinations. Dental decay and tooth wear were scored with the DMFT/deft index and tooth wear index of Smith & Knight, respectively.ResultsThe presence of sleep bruxism was significantly higher in children with parasomnia (p = 0.01; p < 0.05). The presence of tooth wear in children with sleep bruxism was found to be statistically significant (p = 0.032; p < 0.05). It was observed that the presence of sleep bruxism was higher in the children of individuals who smoked at home (p = 0.027; p < 0.05).ConclusionSleep bruxism, untreated dental decay and exposure to early‐life secondhand smoke may have a negative impact on children's sleep habits and characteristics.