Omenihu George ODUALI2024-06-142024-06-142023-12M.EDhttps://repository.lcu.edu.ng/handle/123456789/596Set Theory as a topic in Mathematics in Senior Secondary School that has poised itself as an unclear topic to students due to the unavailability of appropriate interactive materials to teach the topic which in succession leaves the students with limited or no understanding of the topic. This study investigated the ‘’Effect of Interactive Materials Intervention on Senior Secondary School Students’ Academic Achievement in Set Theory in Oyo South Senatorial District. A 2x2x3 quasi-experimental design which involved pretest, posttest and intact group was used for the study. Eighty-five (85) Senior Secondary School Two (SSS2) Students were used from two Senior Secondary Schools. One research question and three hypotheses tested at 0.05 level of significance guided the study. Data were analysed using t-tests and ANCOVA. The results revealed that there was a significant effect of interactive materials’ intervention on the academic achievement of Set Theory in Oyo South Senatorial District (F(1,82) = 50.317, P < 0.05, n 2 = 0.380), there was no significant main effect of gender an senior secondary school students’ academic achievement in set theory in Oyo South Senatorial District ((F(2,81) = 2.545, P > 0.05, n2 = 0.059); there was no significant interaction effect of intervention and gender on Senior Secondary School Students’ academic achievement in set theory in Oyo South Senatorial District (F(1,80) = 2.758, P > n2 = 0.033); there was no significant interaction effect of intervention and subject combination on Senior Secondary School Students’ academic achievement in set theory in Oyo South Senatorial District, Oyo State. It was recommended that curriculum planners and policy makers should make the use of interactive materials a vital part of Mathematics training programs. Keywords: Interactive Materials, Intervention, Mathematics, Set Theory, Senior Secondary School Word Count: 280enInteractive MaterialsInterventionMathematicsSet TheorySenior Secondary SchoolThesis