The focus of the research was to find science teachers' philosophy about the nature of science NOS in philosophical perspectives serving in the public sector universities of Pakistan. The descriptive research method was used to investigate the difference in perceptions of the science teachers about NOS on the basis of gender and subject. An online questionnaire was utilized in order to gather data from respondents. Different constructs of NOS were identified to explore. The female teachers had more understandings about NOS than male teachers. The teachers of mathematics were positivists and decontextualized view of NOS. Male teachers were having an inductivist view of NOS. Physics teachers believed in inductivism. The teachers of chemistry were having process and realism view of NOS. Mathematics teachers were found to have contextualized NOS. It is recommended to provide orientation to science teachers in order to build NOS towards concept clarification during the process of the teaching-learning process.