Emerging research has suggested that engaging learners in argumentation may aid in the development of their NOS views, although this claim lacks empirical support. This study assessed the influence of a professional development program incorporating explicit argumentation in scientific contexts of instruction on five inservice secondary science teachers' views of NOS. Data sources included open-ended questionnaires and interviews. Data analysis indicated there was no substantial development in participants' views of NOS following participation in an argumentation professional development program. These results indicate that a professional development program emphasising explicit argumentation instruction in scientific contexts, without the incorporation of explicit NOS instruction, is not effective in enabling participants' views of NOS to be improved. Implications from this study highlight the importance of including explicit NOS instruction in studies that utilise argumentation as a pedagogical strategy to develop learners' views of NOS.