The study examines the relative effects of Problem-Solving and discussion methods on students achievement and retention in Social Studies.The population for the study comprised 14,867 students and the sample consisted of 360 students (180 males and 180 females).The instrument used for the study was Social Studies Achievement Test (SSAT).The instrument was validated by the researcher and experts.The test-re-test and internal consistency methods of reliability were adopted and the reliability co-efficient of 0.73 and 0.71 were obtained respectively.The data collected were analysed using mean,standard deviation,t-test,Analysis of Variance (ANOVA) and Analysis of Co-variance (ANCOVA).Post hoc analyses were done where necessary using Multiple Classification Analysis (MCA) and Scheffe s test.All the hypotheses were tested at 0.05 level of significance.It was discovered in the study that problem solving method was better than discussion method.Discussion method was also better than conventional lecture method in promoting students achievement and retention in Social Studies.This study recommends that Social Studies teachers use problem-solving and discussion methods in Secondary Sch