In the research; It was aimed to determine the relationship between critical thinking skills and biodiversity literacy of pre-service science teachers. As a research method, comparative causal and relational research models from descriptive approaches were used together. As data collection tools, the Critical Thinking Skills Scale (CTSS) developed by Yoldaş (2009) and the Biodiversity Literacy Scale (BLS) developed by Gürbüz, Derman and Çakmak (2013) were used. In the study, it was found that there was a significant difference between the girls in terms of critical thinking skills of pre-service science teachers, critical thinking skills predicted biodiversity literacy significantly, and pre-service science teachers with high empathy in critical thinking had a high level of knowledge on the concept of biodiversity. In line with the findings, it can be concluded that people with high critical thinking skills also have high levels of biodiversity literacy, or individuals with biodiversity literacy have high levels of critical thinking skills. As a suggestion for future studies, the researches can be expanded by including other regions instead of only the Aegean region, prospective teachers from other branches can be included in the researches, and the research can be conducted with the teachers who graduated together with the prospective teachers.