The size of a classroom significantly influences the teaching and learning process, particularly in subjects like mathematics in Ghanaian schools, where individual attention and active engagement are critical for understanding complex concepts. This study explores the impact of class size on the teaching and learning of mathematics by addressing three key research questions: (1) How does class size affect student achievement in mathematics? (2) What is the relationship between class size and teacher effectiveness in delivering mathematics instruction? (3) How do students perceive the impact of class size on their learning experiences in mathematics? Through quantitative analysis of student performance data, the study aims to provide a comprehensive understanding of how class size influences learning outcomes. Preliminary findings suggest that smaller class sizes are associated with higher student achievement due to increased opportunities for individualized instruction and greater teacher-student interaction. Additionally, teacher effectiveness is often enhanced in smaller classes, as instructors can tailor their teaching strategies to meet the diverse needs of students. Student perceptions indicate that larger classes hinder their ability to actively participate and receive timely support from teachers. The results underscore the importance of optimizing class size to improve the quality of mathematics education. Policymakers and educational institutions should consider class size as a critical factor when designing interventions to enhance teaching practices and student learning experiences. This research contributes to the broader discourse on educational quality by providing actionable insights into how class size affects mathematics instruction and outcomes.