Although the goal of developing school students' understanding of nature of science (NOS) has long been advocated, there is still a lack of research that focuses on probing how science teachers, a kind of major stakeholder in NOS instruction, perceive the values of teaching NOS. Through semi-structured interviews, this study investigated the views of 15 Hong Kong in-service senior secondary science teachers about the values of teaching NOS. These values as perceived by the teachers fall into two types. The first type is related to students' learning of science in the classroom and involves: (i) facilitating the study of subject knowledge, (ii) increasing the interest in learning science, (iii) supporting the conduct of scientific inquiry, (iv) meeting the needs of public examinations, and (v) fulfilling the requirement of learning science. The second type goes beyond learning science and includes (i) developing thinking skills, (ii) cultivating scientific ethics in students, and (iii) supporting the participation in public decisions on socioscientific issues. Although rich relationships were perceived by these teachers between NOS instruction and students' learning of science, few values were stated from broad social and cultural perspectives. Suggestions are made about developing teachers' views of the values of teaching NOS so as to influence their intention of teaching it.