This article explores the nature of a continuing mismatch between curriculum reform rhetoric in science education and actual classroom practice. Lack of philosophical consensus about the nature of science (NOS); lack of appropriate curriculum guidance, classroom materials and pedagogical content knowledge for NOS teaching; teachers' personal theories of learning; and the realities of classroom constraints are all implicated as interacting factors that contribute to the mismatch. Because curriculum policy is political, with pressure brought to bear by many interest groups, it is suggested that the science teaching community cannot adequately address the issues raised in the absence of wider community debate and support.