The study investigates the effect of gender and collaborative learning approach on students' conceptual understanding of electromagnetic induction in Secondary Schools in Nigeria. Three research questions and 2 hypotheses were formulated to guide the research. The research design adopted for this study is the quasi-experimental design. In particular, the design is the non-randomized, pretest-posttest, control group design. The population of the study is made up of the 323 Senior Secondary III physics students in all 6 public co-educational Senior Secondary schools in Port Harcourt local Government area. A sample of 90 students, comprising of 60 male and 30 females were selected for the study. The research instrument developed and used for this study is the Test on Electromagnetic Induction (TOEI). The instrument is composed of 50 questions covering the content area and testing the various levels of understanding. Simple means, standard deviation and variance were used to answer research questions while inferential statistics such as t-test, Analysis of variance (ANOVA) and 2x2 factorial analysis of variance were utilized for the testing of the hypotheses. The results show that gender does not significantly affect the understanding of students in electromagnetic induction when taught with collaborative teaching approach. The study also showed that gender and teaching approaches do not jointly affect students' conceptual understanding of electromagnetic induction at the secondary school level.