This study aims to determine whether the differences in communication skills of students who use the Peer Assessment technique with students who use Teacher Assessment and how much the influences to students. The research method was using pre-experimental design with Intact-Group Comparison. The sample of this research is grade VII students of SMP Negeri 19 Pontianak. The results of observational data analysis of students' communication skills in the experimental class and the control class using the Independent Samples T-test, showed the differences in communication skills between the class using Peer Assessment technique and the class using Teacher Assessment. The result obtained, the average communication skills of students who use the Peer Assessment technique is 66.6 % with a good category and students who use Teacher Assessment is 59.3 % with a fairly good category. Based on the calculation of the effect size obtained results indicate that there is an effect of Peer Assessment on students' communication skills by 0.9 with a high category. Keywords: Students' communication skills, peer Assessment.