Although academic discourse has a reputation for its emotionless objectivity, the emotion of surprise is often expressed in scientific writing. Paradoxically, surprise is cognitive in nature and recognized as a knowledge emotion. Given the connection between surprise and knowledge-making, it is surprising that linguistic expressions of surprise (i.e., surprise markers) in academic discourse have received little research attention. This article reports on an empirical study of surprise markers in research articles. Informed by Charles Fillmore's frame semantics, the study identified and analyzed all the surprise markers in a corpus of 320 research articles. A total of 439 surprise markers were found to evoke seven interconnected semantic frames. These semantic frames contained eight conceptually distinct frame elements, five of which were markedly more frequent than the rest and appeared in 12.76–100% of the frame instances identified. Based on the results of the analyses, a genre-specific Surprise frame with five key frame elements was generalized and is presented in this article as a conceptual tool for understanding how surprise and its linguistic expressions partake in the construction of scientific knowledge. Recommendations are made about how the conceptual frame can inform future research. •Drawing on frame semantics, this study examined surprise as a knowledge emotion.•Surprise markers were identified and classified in a corpus of 320 research articles.•Semantic frames evoked by the surprise markers and their relations were analyzed.•A surprise frame was generalized from the identified frames and key frame elements.•Recommendations are made about the frame as a conceptual tool for future research.