Indiscipline is a major challenge facing schools in Kenya. As a result, the government recommends robust interventions at the school level to rein in on indiscipline. Nevertheless, students continue to exhibit immense behavioural problems. This calls to question the efficacy of the numerous behaviour change interventions put in place. This study assessed the influence of student peer counseling interventions on discipline among public secondary school students in Kiambu County, Kenya. The study was founded on the Ecological Systems Theory (EST). Based on the correlational research design, the study targeted the 227 principals 3,479 guidance and counseling teachers and the 89,065 students in Kiambu County. From these, the study sampled 23 principals, 97 teachers and 398 students using the simple random sampling technique. Data was collected using questionnaires, interview guides, and observation schedules. Piloting was conducted to assist in determining the accuracy, clarity, and suitability of the research instruments. The data was analyzed using descriptive statistics (mean, frequency and percentages) and inferential statistics (Pearson correlation and multivariate regression analysis at a significance level of 0.05). Data from interviews and secondary data sources were subjected to content analysis procedures. The findings show that there was positive and significant correlation between students discipline and student peer counseling (r=0.476, p<0.05). Based on these findings, it is evident that student peer counseling interventions indeed influence students’ discipline in the study area. Interventions around these areas should thus be strengthened to holistically enhance students discipline in the schools studied. The study recommends peer counselors should be frequently recruited and trained by schools to reach more students.