People with back pain regularly search for information online; however, the quality of this online information is often poor. We established a list of the most important messages about diagnosis, imaging, and self-care for people with low back pain, based on consensus opinion and prioritised in order of importance. A list of key messages was derived from clinical practice guidelines for back pain. During 2 survey rounds, a Delphi panel of consumers with back pain and experts rated the importance of each item and suggested additional statements. Messages were retained that were rated as important by more than 70% of the panel. Retained messages were reviewed by consumer focus groups. A priority pairwise ranking activity determined the rank order of the important messages. A final online survey determined the robustness and currency of the final list of statements. The Delphi process and consumer focus groups resulted in 30 unique messages. Experts considered that the most important messages for patients are (1) remain active and (2) reassurance that back pain is a normal experience and not necessarily related to serious harm. This differed from the preferences of people with back pain who prioritised messages related to (1) identification of more serious pathology and (2) principles of management. This list of important key messages about diagnosis, imaging, and general self-care for people with back pain can be used to inform the development of education resources, including new web sites, as well as to direct clinicians in the information they provide to patients.