This study reports the findings on Understand the factors affect student’s academic performance in science subjects in public secondary schools in Tanzania, by drawing references from public secondary schools found at Dodoma Municipal in Tanzania. To achieve this end, the following specific objectives were formulated such as: To examine the availability of teaching and learning materials for science subjects in secondary schools, to identify the pass rate and drop rates in science subjects, to highlight the difficulties or challenges faced by teachers and students in learning science subjects in secondary schools. 30 respondents were selected and data were collected through interviews, observation and documentary review. The analysis of the data revealed that there is congestion of students in class, shortage of laboratories as well as chemicals for practical, lack of enough and quality text books. Furthermore analysis revealed that, teaching and learning of science subjects affected by students and teachers perception, shortage of qualified competent teachers in teaching science subjects. Following the findings researcher suggested that teaching and learning resources in science subjects like books, laboratory apparatus have to be increased to schools to enable students to interact effectively through discussion and other participatory strategies associated in order to improve performance in science subjects. In addition to that, the existence of many students in a single stream affect the teaching and learning process. The government under the ministry of education and vocational training, NGOs and other educational stake holders should have public awareness on the significance of studying science subjects for the current and future development of Tanzania. Those education players should put more emphasize on science subjects and the ministry of education should ensure that all public secondary schools have all resources for teaching and learning.