The study ascertained the influence of peer counselling intervention on the level of alcohol abuse among students in public day secondary schools in Imenti South sub-county, Kenya. The research was implemented using the descriptive survey research design. The study targeted a population of 2000 students who abused alcohol, from the 42 public day secondary schools in the research area. From this figure, 13 Guidance and Counselling teachers and 600 affected students were used as respondents. Simple random sampling technique was employed to select the participating guidance and counseling teachers while snowball sampling technique was used for the affected students. Data for the study were collected using close-ended questionnaires and oral interview schedules. Validity and reliability of these research instruments were verified prior to actual data collection, using the Rasch model and the parallel forms methods respectively. The collected data were analyzed both descriptively and quantitatively, using frequency counts, percentages and themes. Results indicated that the use of peer counselling as an intervention had a significant positive influence on lowering the level of alcohol abuse among affected students in public day secondary schools in Imenti South Sub County.