Inappropriate use of instructional strategies has been widely documented in literature to be one of the major factors for unsatisfactory performance in Mathematics by Senior School (SS) Students. Game-based Instructional strategies have been associated with improved studentsâ€™ performances. Evidence abound in literature that Game-based instructional strategy could enhance studentsâ€™ meaningful understanding of hand-to-learn concept in Mathematics. This study, therefore, investigated the effects of Game-based video Instructional Strategy on Senior School Studentsâ€™ performance in Mathematics in Omu-Aran, Nigeria. The objectives were to: (i) determine the effects of Game-based instructional strategy on the performance of Senior Secondary School students in probability; (ii) determine the performance of Male and Female Students when taught probability using Game-based instructional strategy; (iii) evaluate the performance of students on the basis of their score levels when taught probability with the use of Game-based instructional strategy; (iv) determine the interaction effects of gender and Game-based instructional strategy on studentsâ€™ performance in probability; (v) determine the interaction effects of score level and the Game-based instructional strategy on studentsâ€™ performance in probability; (vi) access the interaction effects of gender, score level and Game-based instructional strategy on studentsâ€™ performance in probability.rnThe study adopted a quasi-experimental design, pre-test, post-test, non-equivalent, non randomised control group. Out of the two randomly selected senior secondary schools, two intact classes consisting of 73 (SS) II students were used as experimental and control groups respectively. The population was 2,032 (SS) students in Omu-Aran, while the target population was 677 (SS) II. The stimulus instrument used in the study was a Coin-Dice video game on probability developed by the researcher, while the test instrument was a Mathematics Performance Test. The reliability coefficient of the instruments were determined through the use of Kendallâ€™s concordance and Pearsonâ€™s Product- Moment Correlation and are found to be 0.53 and 0.71 respectively. Data were analysed using Analysis of Covariance at 0.05 level of significance.rnThe findings of the study were that:rni. a significant difference existed in performance of students taught probability using Game-based instructional strategy and those taught without Game-based; (F(1.70)=32.20, p<0.05);rnii. there was no significant difference in the performance of male and female students taught probability using Game-based instructional strategy;rniii. there was no significant difference in the performance of low, medium and high scoring students taught probability using Game-based instructional strategy;rniv. a significant interaction effect existed between Game-based instructional strategy and gender on the performance of (SS) II students in probability, in favour of female students (F(1.68)=6.17,p<0.05);rnv. there was no significant interaction effect between Game-based instructional strategy and score levels on the performance of (SS) II students in probability; andrnvi. there was no significant interaction effect among Game-based instructional strategy, gender on performance of (SS) II students in probability.rnThe study concluded that Game-based instructional strategy enhanced studentsâ€™ meaningful learning of probability. This implies that Game-based instructional strategy enhance studentsâ€™ performance in Mathematics. The study recommended that Mathematics teachers should make use of Game-based instructional strategy in the teaching of Mathematics.