The secondary school system of education in Nigeria assumes the role of training and producing students for tertiary institutions and manpower for national development and world of work. The general poor academic performance of students in Mathematics has become a source of great concern to all the stakeholders in education particularly the Mathematics educators, parents and the government. Educational Game is one of the strategies that have been found to enhance the attitude and academic achievement of students in many subjects including Mathematics. But many Mathematics teachers lack the knowledge of the role of Mathematical Games. The study therefore, examined the effects of Mathematical Games on senior secondary students’ academic performance in Mathematics in Ejigbo, Osun State, Nigeria. The researchers adopted a quasi-experimental research design and used simple random sampling techniques to select two senior secondary schools for the study. A total of 73 students (32 experimental and 41 control groups) were involved in the study. The experimental group was exposed to Mathematical Games during the teaching of Mathematics for a period of three weeks while the control group was not exposed to Mathematical Games. Mathematics Performance Test (MPT) was used for data collection on students’ academic performance. The findings of the study revealed that the use of Mathematical Games has a significant positive effect on the academic performance of the students in Mathematics; the use of Mathematical Games was beneficial to students irrespective of their gender and scoring ability. It was recommended among other things that the government should provide Mathematical Games for secondary school students and Mathematics teachers should incorporate the use of Mathematical Games into the teaching and learning of Mathematics.