Purpose New physicians need to master non-technical skills (NTS), as high levels of NTS have been shown to increase patient safety. It has also been shown that NTS can be improved through training. This study aimed to establish the necessary NTS for Norwegian medical students to create a tool for formative and summative assessments. Methods Focus group interviews were conducted with colleagues and patients of newly graduated physicians. Interviews were then analyzed using card sort methods, and the identified NTS were used to establish a framework. Focus groups commented on a prototype of an NTS assessment tool. Finally, we conducted a search of existing tools and literature. The final tool was developed based on the combined inputs. Results We created Norwegian medical students' non-technical skills (NorMS-NTS) assessment tool containing four main categories; together comprising 13 elements and a rating scale for the NTS of the person observed. Conclusions The NorMS-NTS represents a purpose-made tool for assessing newly graduated physicians' NTS. It is similar to existing assessment tools but based on domain-specific user perspectives obtained through focus group interviews and feedback, integrated with results from a literature search, and with consideration of existing NTS tools.