The efforts shown in recent years related to the reform movements in science education have focused on the assertion that informed nature of science understandings (NOS, hereafter) should be developed. In line with this idea, NOS has become the central component of numerous science curricula. In the study, therefore, it was aimed to determine science education master students' NOS understandings. The study was conducted in a state university in Turkey during the fall semester of the 2019-2020 academic year and included six science education master students who had taken science methods course. The data were collected through interviews and analyzed by content analysis under phenomenological method. As a result, the students had various and mixed understandings related to the definition of science and characteristics of scientific knowledge. In addition, it was observed that the students handled science with a narrow scope, that they had difficulty in the distinction between theory and law, and that they could not develop informed understandings in the component of theory-laden NOS. In light of these results, the implications and the directions for further study were provided.