The purpose was to examine NOS knowledge and pedagogical content knowledge about NOS of in-service secondary science teachers. Data sources included Views of Science and Education scale, lesson plans with rationales for choices, examples of student work products, videotapes of lesson peer reviews, and interviews conducted after the experience. Teachers scored significantly higher on several aspects of NOS knowledge and on one aspect of attitudes toward teaching NOS on the VOSE. Scaffolded NOS professional development with analysis of student work products resulted in NOS lessons that had a higher level of inquiry, and deliberate explicit and reflective instruction. (Contains 4 tables and 1 figure.)