This study employed a word association test to determine middle school students' cognitive perceptions and misconceptions of the key concepts regarding "cycles of matter and environmental problems." The study adopted descriptive research in survey model. The sample consisted of 457 eighth-grade students from four middle schools affiliated with the Ministry of National Education (MoNE) in the central district of Mus province in the 2020-2021 academic year. Data were collected using a word association test developed by the researcher. The test addressed eight key concepts: "water cycle," "nitrogen cycle," "oxygen cycle," "carbon cycle," "ozone layer," "global warming," "greenhouse effect," and "ecological footprint." The data were analyzed using content analysis. Concept networks were created based on participants' responses. Participants associated "water cycle," "nitrogen cycle," "oxygen cycle," "carbon cycle," "ozone layer," "global warming," "greenhouse effect," and "ecological footprint" with "evaporation," "lightning," "photosynthesis," "carbon dioxide," "ozone hole," "melting of glaciers," "global warming," and "humans," respectively. Participants did not make adequate associations with oxygen cycle, which was one of the key concepts. It was found that participants did not know enough about the key concepts from the sentences they wrote, preventing them from making scientific statements. They mostly had unscientific and superficial remarks and misconceptions. Within the scope of the research, it is recommended that teachers create effective learning environments where they can use different methods and techniques to help students eliminate misconceptions.