The main purpose of this study is to examine the epistemological beliefs and informal reasoning of science and social studies teachers about COVID-19, which is a controversial socioscientific issue. Qualitative research, specifically phenomenological design, was used in the study. During the data collection process, teachers' epistemological beliefs, reasoning skills and perceptions of COVID-19 were elicited using the Semi-Structured Interview Protocol (SSIP) developed by the researchers. Categorical analysis, a type of content analysis, was used in the examination of qualitative data. As a result of the research, it was found that teachers' epistemological beliefs about COVID-19 are formed in order to define and explain the source of this information. In contrast, it was found that while the most common sources of information about COVID-19 are the internet, the environment, and intuition, the least used source of information is scientific publications. Teachers failed to provide sufficient evidence to substantiate their claims and found it difficult challenging scientific arguments to bolster their own opinions. Science teachers believe that the main purpose of teaching social science issues is to develop scientific process skills. Social studies teachers believe that the main purpose is to develop a sense of citizenship and the thinking and decision-making skills that individuals need to solve social problems.