This study explored the link between teachers’ inputs and process and students’ academic achievement in Junior Secondary Certificate (JSC) Mathematics for the period 2006 to 2010.The outcome (teacher effectiveness) was obtained by means of value added measures (students’ aggregate JSC Mathematics scores for 2006 to 2010 by school). One hundred and fifty JSC schools out of a total of 573 constituted the units of analysis for the study. The data regarding teachers were obtained by means of self-administered questionnaires, and JSC Mathematics results from 2006 to 2010 were obtained from the Directorate of National Examinations and Assessment (DNEA). Multi-correlation and regression techniques at alpha =0.001; 0.05 and 0.10 were used to analyse the link between teachers’ inputs and processes, and students’ academic achievement in JSC Mathematics. The null hypotheses formulated for the study were tested at the 0.05 (5%) level of significance. In summary, it appears that the various aspects of teachers’ inputs (teachers’ educational qualifications, teaching experience, subject specialisation etc.), processes (standards-based professional development, standards-based classroom activities, and classroom management beliefs) are related to students’ academic achievement in JSC Mathematics. In particular, a linear combination of the following variables had a significant and positive association with students’ academic achievement in JSC Mathematics: teachers’ major in Mathematics (teachers’ inputs); teachers’ usage of whole class discussion (standards-based classroom activities); perceived knowledge of algebra; teachers’ professional development in interdisciplinary instruction; teachers’ review of students’ homework/assignments; and students talking to other students about how to solve mathematics problems. Teachers’ pedagogical content knowledge (PCK) in general, and some classroom practices were not significantly related to students’ academic achievements. This study, therefore, recommends that teachers’ professional development should focus on the subject matter that the teachers will be teaching, as well as alignment of teachers’ learning opportunities with real work experience using actual curriculum materials and assessment.