This study examined the relationship between Teachers’ mathematics teaching self-efficacy, Use of mathematics instructional materials and Students’ achievement in secondary school mathematics. Descriptive survey of the correlation type was adopted for this study. Simple random sampling technique was used to select three Educational Districts out of the six Educational Districts in Lagos State, while stratified random sampling technique was used to select 40 schools from each of the selected Educational Districts. Six SSII students and their mathematics teacher were selected from each of the 40 schools, making a total of 120 teachers and 720 students who were used as the participants of this study. The three valid and reliable instruments used to collect data were the; Mathematics teaching Self-efficacy Scale (MTSES), Questionnaire on utilization of mathematics instructional materials (QUMIM) and Mathematics achievement test (MAT). Their test retest reliability values were 0.82, 0.87 and 0.84 respectively using Kuder-Richardson (KR-20)’s formula. The result of the Pearson correlation and Multiple regression analyses show that: There is a significant positive relationship between the teachers’ mathematics teaching self-efficacy and utilization of mathematics instructional materials; there is a significant positive relationship between the teachers’ utilization of mathematics instructional materials and students’ achievement in mathematics; there is a significant relationship between teachers’ mathematics teaching self-efficacy and students’ achievement in mathematics; the two predictor variables jointly accounted for 45.2% variations in students’ academic achievement in mathematics. It is recommended that, Government and school heads should make mathematics instructional materials available in secondary schools; Self-efficacy enhancement programme should be organized for the mathematics teachers to enable them develop self confidence in their ability to effectively impact knowledge in their students.