The study

investigated the effects of peer assessment on students’ academic achievement

in junior secondary school computer science. The study employed

quasi-experimental design. The study was conducted on two secondary schools. In

one of the schools intact class of Jss II was assign to the treatment group

while in the other secondary school the intact class Jss II were assigned to

the control group. The treatment group was taught concepts in measures of

central tendency in Microsoft excel software using a peer assessment

instructional package (PAIP) while the control group was taught concepts in

measures of central tendency in Microsoft excel software using conventional

teaching package. Simple random sampling technique was adopted in choosing the

two secondary schools out of which 120 junior secondary school II students were

selected from the sample schools. Three research questions and three null

hypotheses guided the study. Computer achievement test (CAT) was use to collect

data for the study. The data was analyzed using mean, standard, deviation and

analysis of covariance (ANCOVA). The result revealed that peer assessment which

is a method of assessment where by learners are allowed to assess their peers

and give feedback based on a given rule had significant effect on students’

academic achievements in computer science. The study also revealed that the

difference in the mean achievement of male and female students taught using

peer assessment method is not statistically significant. The study recommended

that peer assessment strategy should be used by teachers in the teaching and

assessment of student in computer science subject.