This research aims to examine the effect of peer teaching on the academic success of primary school fourth grade students. The biggest difference of this research from other researches is the application of a different method in peer teaching. This research is in the pretest-posttest experimental design with an unequal control group. The research sample consists of fourth-grade students in a primary school in the province of Alanya, Antalya, Turkey. There are two fourth-grade classes in the primary school. One of these classes was determined as the experimental group and the other as the control group. There are 32 students in the experimental group. There are 28 students in the control group. The primary school fourth grade academic achievement test developed by the researchers was used as a data collection tool. The research was carried out in December 2021 and January 2022. A seven-week application was made in the fourth grade of a primary school in Alanya as part of the study project. Students in the fourth grade of a primary school participated in an experimental technique. SPSS 25 program was used in the analysis of the data. The statistical test computed was a t-test analysis, indicating that the peer teaching experimental group have a mean of 62,96 on the academic achievement scale. But the control group has a mean of 47,85, a difference of 15,11 points between the two groups. The two-tailed significance test indicates a two-tailed p-value of p=0,001. This p value is statistically significant because it is less than alpha =0,05. Peer teaching increased students' academic achievement significantly.