Abstract: The main purpose of this study is to investigate the effects of Jigsaw on the academic achievement of junior secondary school students in social studies in Nsukka, Nigeria. Specifically, the study investigated the effect of Jigsaw on the academic achievement of students in Social Studies and determined gender differences among students exposed to Jigsaw. Two research questions and one hypothesis guided the study. Social Studies Concept Test (SSCT) was used to collect data. The study is a quasi-experimental study of a non-equivalent design. Four social studies teachers from the schools that were used formed the research assistants. The research assistants were used both in teaching and administration of the instrument. The data that were collected were analyzed using Analysis of Covariance (ANCOVA) to test the hypothesis and mean and standard deviation to answer the research questions. The findings showed no significant difference in the mean achievement of male and female students in social studies.