BACKGROUND: Oral health behaviours such as establishing twice-daily toothbrushing and sugar control intake need parental self-efficacy (PSE) to prevent the development of childhood dental caries. A previous study has shown that behaviour change techniques (BCTs) delivered via a storybook can improve parental self-efficacy to undertake twice-daily toothbrushing. OBJECTIVE: to determine whether an intervention (BBaRTS, Bedtime Brush and Read Together to Sleep), designed to increase PSE; delivered through storybooks with embedded BCTs, parenting skills and oral health messages, can improve child oral health compared to (1) an exactly similar intervention containing no behaviour change techniques, and (2) the BBaRTS intervention supplemented with home supply of fluoride toothpaste and supervised toothbrushing on schooldays. METHODS/DESIGN: A 2-year, three-arm, multicentre, cluster randomised controlled trial. PARTICIPANTS: children (estimated 2000-2600) aged 5-7 years and their families from 60 UK primary schools. INTERVENTION: Test group 1: a series of eight children’s storybooks developed by a psychologist, public health dentist, science educator, children’s author and illustrators, with guidance from the Department for Education (England). The books feature animal characters and contain embedded dental health messages, parenting skills and BCTs to promote good oral health routines focused on controlling sugar intake and toothbrushing, as well as reading at bedtime. Books are given out over 2 years. Test group 2: as Test group 1 plus home supplies of fluoride toothpaste (1000 ppmF), and daily supervised toothbrushing in school on schooldays. Active Control group: series of eight books with exactly the same stories, characters and illustrations, but without BCTs, dental health messages or parenting skills. Annual child dental examinations and parental questionnaires will be undertaken. A sub-set of participants will be invited to join an embedded study of the child’s diet and salivary microbiota composition. PRIMARY OUTCOME MEASURE: dental caries experience in permanent teeth at age 7-8 years. DISCUSSION: A multi-disciplinary team was established to develop the BBaRTS Children’s Healthy Teeth Programme. The books were developed in partnership with the Department for Education (England), informed by a series of focus groups with children, teachers and parents. TRIAL REGISTRATION: ISRCTN21461006 (date of registration 23 September 2015).