This study investigated the effect of the flipped learning approach on the academic performance and retention of undergraduate students in trigonometry in Kebbi State, Nigeria. A quasi-experimental design was employed, involving 140 students divided into an experimental group (taught using flipped learning) and a control group (taught using traditional methods). The Trigonometry Achievement Test (TAT) was administered as a pretest, posttest, and delayed posttest (after four weeks) to measure performance and retention. Results indicated that the flipped learning group significantly outperformed the control group in both academic performance (mean difference) and retention (mean difference). No significant gender differences were found in either performance or retention. The findings suggest that flipped learning enhances trigonometry learning outcomes and retention more effectively than traditional methods, supporting its adoption in undergraduate mathematics education.
Keywords: : Academic Performance, Nigeria, Retention, Undergraduate Students, flipped learning, trigonometry