To determine patients', nurses' and researchers' opinions on the appropriateness and completeness of the proposed conceptualization of nurses' support of hospitalised patients' self-management. A modified Delphi study. We conducted a two-round Delphi survey. The panel group consisted of patients, nurses and researchers. The conceptualization of nurses' support of hospitalised patients' self-management presented in the first Delphi round was based on previous research, including a scoping review of the literature. Data was analysed between both rounds and after the second round. Results are reported in accordance with the guidance on Conducting and Reporting Delphi Studies (CREDES). In the first round all activities of the proposed conceptualization were considered appropriate to support the patients' self-management. Panel members' comments led to the textual adjustment of 19 activities, the development of 15 new activities, and three general questions related to self-management support during hospitalisation. In the second round the modified and the newly added activities were also deemed appropriate. The clarification statements raised in the first Delphi round were accepted, although questions remained about the wording of the activities and about what is and what is not self-management support. After textual adjustments and the addition of some activities, the proposed conceptualization of nurses' support in patients' self-management while hospitalised have been considered appropriate and complete. Nevertheless, questions about the scope of this concept still remains. The results provide a starting point for further discussion and the development of self-management programs aimed at the hospitalised patient. The results can be considered as a starting point for practice to discuss the concept of nurses' support for hospitalised patients' self-management and develop, implement and research self-management programs specific for their patient population. Results are reported in accordance with the guidance on Conducting and Reporting Delphi Studies (CREDES). Patients were involved as expert panellist in this Delphi study. Impact statement What problem did the study address? Self-management support during hospitalisation is understudied, which undermines the development of evidence-based interventions. What were the main findings? A panel, consisting of patients, nurses and researchers, agreed on the appropriateness of a conceptualization of nurses' support of inpatients' self-management, and identified some points for discussion, mainly related to the boundaries of the concept self-management. Where and on whom will the research have an impact? This study is crucial for generating conceptual understanding of how nurses support patients' self-management during hospitalisation. This is necessary for policy, clinical practice, education, and research on this topic.