The classroom serves as the heart of the educational system's production. It is clear that the classroom management and organization by teachers will help students learn. Students should be able to be comfort and at ease in the classroom because it is the place they spend most of their time. The study looked at how effective classroom management strategies and techniques employed in a few chosen junior high schools affected students' behaviour and academic performance in the Sekondi-Takoradi Metropolis. The study's design was a cross-sectional survey. Sixteen (16) teachers who teach only the core subjects and 229 students were chosen using the purposive and lottery sampling techniques respectively to participate in the Behaviour and Instructional Management Scale (BIMS) survey. Frequencies, percentages, means, standard deviations, Pearson's Product Moment Correlation Coefficient (PPMCC), and independent samples t-test were employed as statistical methods for data analysis. The study's findings indicated that the most often employed classroom management techniques were good relationships with students and reinforcement, according to both students and teachers. Both the antecedent strategy and reinforcement strategy were found to have a substantial positive association with the academic performance and behaviour of students. The study advises teachers to concentrate on strategies for classroom management that work, such as reinforcement. The Ghana Education Service should continue its tradition of providing teachers with ongoing in-service training. This will guarantee that teachers are exposed to contemporary teaching methods and new trends.