The purpose of this study was to investigate the effects of class size on the effective teaching and learning of computer in junior secondary schools in Ushongo, Benue State. The study was motivated by concerns that large class sizes may hinder effective teaching and learning of computer due to the limited interaction between teachers and students. The study employed a mixed-methods approach, including both quantitative and qualitative data collection methods. The population of the study comprised of 14 public junior secondary schools in Ushongo, Benue State. The sample size consisted of 300 students who were selected using simple random sampling technique. Data were collected using questionnaires, interviews, and observation checklists. The study found that large class size negatively affects the quality of teaching and learning of computer. The study recommended that the government should ensure that the teacher-student ratio is maintained at an optimal level to enhance the quality of teaching and learning of computer in junior secondary schools.