This study aims to investigate the relationships among epistemological beliefs, metacognitive awareness, and nature of science (NOS). Participants were 45 preservice science teachers (PSTs) enrolled in two sections of Laboratory Application in Science II course in a university in Turkey. All of the participants were juniors with the same science major background. Participants in both groups were engaged with explicit-reflective and inquiry-based NOS instruction under conceptual change theory. This study is considered as a mixed methods concurrent embedded design model. After the intervention, all of the PSTs demonstrated developments about many of the NOS aspects. It can be concluded that inquiry-based laboratory instruction informed by the conceptual change theory provided PSTs' improve their NOS understanding. This study revealed statistically significant relationships among the some aspects of NOS, epistemological beliefs, and metacognitive awareness. The relationships were discussed in respect to current science education literature. (Contains 7 tables.)