RESUMEN
BACKGROUND: Sleep bruxism (SB) is a masticatory muscle activity that affects children. Parents' knowledge is important for its identification and report to dentists. AIM: To investigate parents' knowledge about SB among their children. DESIGN: A cross-sectional study included 1325 parents of children from dental clinics of seven institutions from all regions of Brazil. Parents answered questions about child's sleep, knowledge about SB and its occurrence among children and parents. SB definition given by parents was dichotomized as "correct"/"incorrect", based on the American Academy of Sleep Medicine definition. Descriptive, bivariate and multivariate analyses were performed (P < 0.05). RESULTS: Most parents (57.3%) did not know what SB is and 88.9% would like to receive more information. SB prevalence among parents was 15.4% and 24.0% among children. Between parents who correctly defined SB, its prevalence increased to 27.5% among parents and 40.6% among children. Parents whose children had/have SB, who would like to receive more information about SB and were from the North, Central-West, Southeast, and South regions were more likely to define SB correctly (P > 0.05). CONCLUSION: There is a lack of knowledge of parents about SB. SB among children, parents' interest in receiving more information and their location were factors associated to their knowledge.