The study investigated the effects of Geoboard on Secondary Students’ Mathematics performance and retention in Ogbia, Local Government Area, Bayelsa State. Pre-test, post-test non-equivalent quasi-experimental design was employed for this study. Two research questions guided the study. Out of a total population of four hundred and fifty (450) Mathematics students in six (6) public secondary schools, a total of one hundred and sixty-three (163) students from three co-educational secondary schools purposively selected formed the sample size of the study. Geometry Performance Test (GPT) which also tested retention with a reliability index of 0.85 was developed. Research questions were answered with mean and standard deviation. The results revealed that Geoboard proved more effective than lecture method in students’ understanding of geometry. Furthermore, the study noted that Geoboard are effective learning strategies for enhancement of students’ retention in Geometry. It was recommended that Geoboard should be used by Mathematics teachers to teach geometry so as to enhance students’ performance and retention in Mathematics.