The purpose of this study was to explore the effect of the inquiry-based and explicit-reflective laboratory instruction on preservice science teachers' (PSTs) conceptions of the nature of science (NOS) aspects. This study was carried out during the Laboratory Application in Science II course. All 52 preservice elementary science teachers enrolled in the course consented to participate in the study; 37 were female and 15 were male, with a mean age of 22.8 years. All had the same science major background, and all of them were juniors. The course provided meaningful and practical inquiry-based experiences, as well as explicit and reflective instruction about NOS. Each week, a specific NOS aspect was targeted related to the inquiry-based laboratory investigation. The design of the study was qualitative and exploratory in nature. At the beginning of the study, the Views of Nature of Science Questionnaire Version B open-ended questionnaire was applied to explore PSTs' NOS views. At the end of the semester, the same questionnaire was conducted to determine the impact of the explicit-reflective and inquiry-based laboratory instruction. The results showed that many PSTs improved their views of NOS in each element, although to different degrees.