The main concern in education sector is how teaching methods affect students’ performance. This study examined teaching methods on performance of students in public secondary schools (A-level) in Tanzania where Nyamagana District in Mwanza was used as a case of study. The study was guided by three specific objectives: To identifying teaching methods used in instruction of science subjects in public secondary school, to assess students’ perception of the appropriateness of teaching methods used in teaching in public secondary school and to determine the level of relationship between teaching methods and students’ performance in public secondary schools in Nyamagana District, Mwanza. The study applied descriptive research designed that incorporated qualitative and quantitative approach. The sample of teachers 78, students 129 and inspectors 9 was surveyed using in-depth interview and questionnaire. Qualitative data was analyzed descriptively using SPSS while thematic analysis was used to analyzed qualitative data. The study findings revealed that most effective teaching methods were demonstration followed by question and answers and then brainstorming, teachers should know the value and impact of different teaching methods and regular training/workshop should be conducted on teaching methods. The study recommended that traditional methods like lecture should not be used. The study also suggested other areas for further research as the same study should be carried in other district before generalization is done and similar research also should be conducted in private schools to know the teaching conditions.