The purpose of this study was twofold: first, to investigate science teachers' views about the nature of science (NOS); and second, to examine science teachers' views about their NOS integration into instruction. Reconceptualized family resemblance approach to nature of science (RFN) is used as a theoretical and analytical framework. The participants of this study included 13 in-service science teachers in Turkey, and the data were collected through semi-structured interviews. It is noticed that teachers used scientific practices and scientific methods interchangeably. Participants provided detailed explanations regarding the social-institutional system of science. Participants' views and interpretations were compatible with the RFN framework, which can show that they were aware of the social aspect of science. Concerning the NOS integration into instructions, findings revealed that teachers who had spent more time on NOS tended to include or thought it is important to include NOS into science lessons. Based on the results, it is suggested that the RFN framework can be used as both an analytical and theoretical framework to investigate teachers' understanding of NOS.