This study suggests that cultivating NOS education is a difficult and challenging task. For more than a decade of explicit inclusion of NOS in the basic education curriculum of Thailand, NOS is generally believed to have become deeply rooted in Thai science teachers and their classrooms. However, this study reveals that Thai science teachers still possess many uninformed conceptions of NOS. In addition, one NOS study conducted in the Thai context indicates that science teachers' conceptions of NOS are stable and resistant to change.