This study assessed the influence of a 3-year professional development program on elementary teachers' views of nature of science (NOS), instructional practice to promote students' appropriate NOS views, and the influence of participants' instruction on elementary student NOS views. Using the VNOS-B and associated interviews the researchers tracked the changes in NOS views of teacher participants throughout the professional development program. The teachers participated in explicit-reflective activities, embedded in a program that emphasized scientific inquiry and inquiry-based instruction, to help them improve their own elementary students' views of NOS. Elementary students were interviewed using the VNOS-D to track changes in their NOS views, using classroom observations to note teacher influences on student ideas. Analysis of the VNOS-B and VNOS-D showed that teachers and most grades of elementary students showed positive changes in their views of NOS. The teachers also improved in their science pedagogy, as evidenced by analysis of their teaching. Implications for teacher professional development programs are made. (Contains 2 tables.)