- BACKGROUND: Children who stutter (CWS) are at a high-risk of being teased and bullied in primary school because of negative peer attitudes and perceptions towards stuttering. There is little evidence to determine if classroom-based interventions are effective in changing peer attitudes towards stuttering. The primary objective is to determine the effect of the Classroom Communication Resource (CCR) intervention versus usual practice, measured using the Stuttering Resource Outcomes Measure (SROM) 6-months post-intervention among grade 7 students. The secondary objective is to investigate attitude changes towards stuttering among grade participants on the SROM subscales. METHODS: A cluster randomised controlled trial (RCT) will be conducted with schools as the unit of randomization. Schools will be stratified into quintile groups, and then randomized to receive the CCR intervention or usual practice. Quintile stratification will be conducted in accordance to the Western Cape Department of Education classification of schools according to geographical location, fee per school and allocation of resources and funding. Participants will include primary schools in the lower (second and third) and higher (fourth and fifth) quintiles and children aged 11 years or older in grade 7 will be included. The study will consist of the CCR intervention program or usual practice as a no-CCR control. The CCR is a classroom-based, teacher led intervention tool including a story, role-play and discussion. The grade 7 teachers allocated to the CCR intervention, will be trained and will administer the intervention. The analysis will follow intention-to-treat (ITT) principle and generalized estimating equations (GEE) to compare groups on the global SROM and its subscales to account for possible clustering within schools. The subgroup hypothesis will be tested by adding an interaction term of quintile group x intervention. DISCUSSION: This study is designed to assess whether the CCR intervention versus usual practice in schools will lead to positive shift in attitudes about stuttering at 6-months post-intervention among grade 7 participants. TRIAL REGISTRATION: The trial number is NCT03111524 . It was registered with clinical trials.gov Protocol registration and results system (PRS) retrospectively on 9 March 2017.