PURPOSE: In clinical settings, uncertainty is part of everyday practice. However, a lack of insight into how experts approach uncertainty limits the ability to explicitly teach and assess it in training. This study explored how experienced surgeons perceived and handled uncertainty during challenging intraoperative situations, to develop a theoretical language supporting both education and research. METHOD: This constructivist qualitative study included observations and interviews during 26 surgical cases. The cases, drawn from seven staff surgeons from various specialties at a medical school, were purposively sampled after being preidentified by the surgeon as "likely challenging." The authors combined template and inductive analyses. In template analysis, an existing theory was used to identify instances of uncertainty in the dataset. Inductive analysis was used to elaborate and refine the concepts. RESULTS: Template analysis confirmed that existing theoretical concepts are relevant to surgery. However, inductive analysis revealed additional concepts and positioned existing concepts within new relationships. Two new theoretical themes were recognizing uncertainty and responding to uncertainty, each with corresponding subthemes. Factors such as the novelty of the situation, difficulty in predicting the outcome, and difficulty deciding the course of action mainly characterize an uncertain situation in surgery according to the participants. CONCLUSIONS: The results offer a refined language for conceptualizing uncertainty in surgery. Although further research could elaborate and test the explanatory power of this language, the authors anticipate that it has implications both for current discussions of surgical safety and for future development of explicit training for effective management of surgical uncertainty.