The inclusion of Nature of Science in the science curriculum has been advocated around the world for several decades. One way of defining NOS is related to the family resemblance approach. The family resemblance idea was originally described by Wittgenstein. Subsequently, philosophers and educators have applied Wittgenstein’s idea to problems of their own disciplines. For example, Irzik and Nola adapted Wittgenstein’s generic definition of the family resemblance idea to NOS, while Erduran and Dagher reconceptualized Irzik and Nola’s FRA-to-NOS by synthesizing (...) educational applications by drawing on perspectives from science education research. In this article, we use the terminology of “Reconceptualized FRA-to-NOS ” to refer to Erduran and Dagher’s FRA version which offers an educational account inclusive of knowledge about pedagogical, instructional, curricular and assessment issues in science education. Our motivation for making this distinction is rooted in the need to clarify the various accounts of the family resemblance idea.The key components of the RFN include the aims and values of science, methods and methodological rules, scientific practices, scientific knowledge as well as the social-institutional dimensions of science including the social ethos, certification, and power relations. We investigate the potential of RFN in facilitating curriculum analysis and in determining the gaps related to NOS in the curriculum. We analyze two Turkish science curricula published 7 years apart and illustrate how RFN can contribute not only to the analysis of science curriculum itself but also to trends in science curriculum development. Furthermore, we present an analysis of documents from USA and Ireland and contrast them to the Turkish curricula thereby illustrating some trends in the coverage of RFN categories. The results indicate that while both Turkish curricula contain statements that identify science as a cognitive-epistemic system, they underemphasize science as a social-institutional system. The comparison analysis shows results such as the “scientific ethos” category being mentioned by the Irish curriculum while “social organizations and interactions” category being mentioned by the Turkish curriculum. In all documents, there was no overall coherence to NOS as a holistic narrative that would be inclusive of the various RFN categories simultaneously. The article contributes to the framing of NOS from a family resemblance perspective and highlights how RFN categories can be used as analytical tools. (shrink)