The study investigated the effect of Peer Assessment Techniques (PAT) on students’ academic achievement in senior secondary Computer studies in Enugu Education Zone. Two research questions and two null hypotheses guided the study. A Quasi-experiment of non-randomized control group pretest-posttest design was adopted. Two public owned secondary schools from Enugu Education Zone with a total of 113 SS2 students from 3916 students were involved in the study. Two intact classes were used, one intact class for the experimental group and one for the control group. The instrument for data collection was Computer Achievement Test (COAT), formulated and adopted by the researcher. The reliability of the instrument was estimated using Cronbach Alpha, while the validation was done by three specialists; two from measurement and evaluation and one from Computer science Education. Analysis of covariance (ANCOVA) at 0.05 probability level was used to test the null hypotheses, while mean and standard deviation were used to answer the research questions. The result of the analyses indicated that the effect of PAT on students’ academic achievements in secondary school computer studies was significant. Gender was not a significant factor on students’ achievement. Thus, it is recommended that Computer studies teachers should adopt the use of PAT in assessing students since it seemed to be more effective in improving students’ achievement in Computer studies. Also, the government should organize workshops, conferences and seminars to train teachers in the use of PAT