This work investigated effect of peer-tutoring on senior secondary school students’ academic performance in mathematics in Ahoada East Local Government Area of Rivers State. The study adopted quasi experimental research design of pre-test, post-test non-equivalent group design. This was premised on the fact that; there has been poor performance of students in both internal and external examinations among the senior secondary school students in Mathematics in the schools. Two research questions and two hypotheses were formulated to guide the study. A sample size of one hundred and ninety- five (195) students was drawn from a population of four thousand, one hundred and fifty-eight (4,158) SS 2 students. Mathematics performance test (MPT) and lesson notes (LN) were the two instruments used for data collection. The face and content validities of the instrument was done by three experts in Educational Measurement and Evaluation in the Department of Guidance and Counselling, Ignatius Ajuru University of Education. A reliability coefficient of 0.76 was obtained for the MAT using test-re-test reliability method. The data collected were analysed using mean, standard deviation and ANCOVA which were tested at 0.05 level of significance. The result of the findings revealed that students taught Mathematics using Peer Tutoring Strategy performed better than those taught using Conventional Teaching Method. It is therefore recommended that peer tutoring strategy be incorporated in the teaching of other subjects.