This qualitative study explores the epistemic climate in a fourth-grade science lesson about woodlands as an ecosystem. The Educational Model of Personal Epistemology (EMPE) was operationalized as a research framework to define components and relations of the epistemic climate. Semi-structured interviews, classroom observations, and document analyses were conducted to investigate the epistemic beliefs of the teachers and students as well as the epistemic underpinnings of instruction and educational materials and were triangulated to describe the overall nature of the epistemic climate of the 60-minute lesson. The results describe an epistemic climate that was dominated by an overall absolutistic pattern (along the dimensions of stability, source, and justification) with an evaluativistic notion (along the dimension of structure). The epistemic belief pattern of Mrs. M was mainly evaluativistic in nature, while the epistemic patterns of her students, instruction, and educational materials were more absolutistic. Conceptual, developmental, and educational implications are discussed.