The correct perception and comprehension of environment by students is influential on developing, in them, interest, awareness, and a positive attitude about acquiring environmental knowledge. Thus, examining the perception of the concept environment is important. The capability of teachers to perceive the environment in a correct and holistic way may contribute to the proper construction of these concepts in students' minds and the development of positive attitudes towards the environment among the students. This study aimed to determine the environmental perceptions of pre-service science teachers. Method: In this study, one of the qualitative research designs – case study design, was used. This study was a holistic single-case design. The Word Association Test (WAT) containing the key concept environment was administered to 122 pre-service science teachers. The students were asked to write their answers about the key concept and then construct sentences in 30 seconds involving the given answers. The answers of the students about the key concept were examined under four main themes: “natural environment”, “artificial environment”, “environmental problems”, and “emotions and situations”. The theme “natural environment” was divided into following sub-themes: “living elements”, “nonliving elements”, and “ecological concepts”.Discussion, Conclusion, and Implications: The analysis of the students' answers about the key concept showed that the perceptions of the students about natural environment varied more in comparison to their perceptions about artificial environment. It was seen that living beings were featured prominently in the perceptions of the pre-service teachers participating in the study. The research results indicated that most students had an anthropocentric environmental perception. Another observation about living elements was the association of environment with family and society. A limited number of answers were given in regard to nonliving elements. The most frequently given answer was “weather”. Thus, the pre-service teachers had a low-level perception regarding nonliving elements. Under the sub-theme ecological concepts, environment was associated with nature and forest involving living and nonliving beings by many pre-service teachers. The participants associated environment with natural environment to a great degree. Under the theme artificial environment, “house” and “building/apartment” were most frequently stated by the students. The majority of the students associated environment with environmental problems such as pollution and garbage. It was also observed that the students associated environment with many situations and emotions including “cleanness”, “life”, and “happiness”. The literature review indicated that most of the research focusing on perception and comprehension regarding environment was conducted at middle school level. A remarkable aspect of the present study is that the perceptions of the students were highly similar despite the age difference between them. It can be concluded that the environmental perceptions of students continue to be limited even after rise in their educational levels. Especially the fact that the study group consisted of pre-service science teachers, who are expected to lay the foundations of environmental education, reveals that more research should be conducted in this field, and pre-service teachers should be educated effectively about environment. The results obtained in the present study highlight that there are certain deficiencies in efforts to create an environmental perception that is integrated, ordered, and functional within itself as stated in today's scientific discourse. These results also reveal that the teaching of environmental concepts and situations should be designed and implemented within the framework of environmental science data.