BackgroundChildren with cleft lip and/or palate (CLP) are prone to poorer oral health outcomes than their peers, with serious implications for treatment. Little is known of the knowledge and practice of children with CLP in caring for teeth and how these contribute to oral health. AimTo investigate (i) parents' and children's knowledge of oral health, (ii) how knowledge is acquired, and (iii) how knowledge is implemented. DesignA qualitative design was used to investigate knowledge, beliefs, and practices reported by parents and children, age 5-11 years with CLP. Data were collected from 22 parents and 16 children and analysed using thematic analysis. ResultsFour themes were derived as follows: (i) implicit knowledge: children express simple knowledge underpinned by basic rationales, (ii) situated knowledge: children gain skills as part of everyday childhood routines, (iii) maintaining good practice in oral health: parents take a lead role in motivating, monitoring, and maintaining children's toothbrushing, and (iv) learning opportunities: pivotal moments provide opportunities for children to extend their knowledge. ConclusionDevelopers of oral health education interventions should take account of children's implicit knowledge and the transmission of beliefs between generations that influence toothbrushing behaviours. This could enhance interventions to support parents and children's practice.