ObjectiveThere is a growing concern about the sustainability of healthcare and the impacts of ‘overuse’ on patients and systems. Quaternary prevention (P4), a concept promoting the protection of patients from medical interventions in which harms outweigh benefits, is well positioned to stimulate reflection and inspire solutions, yet has not been widely adopted. We sought to identify enablers and barriers to a P4 approach, according to field experts and advocates in one health system.DesignQualitative methodology, using semistructured interviews and a grounded theory approach facilitated thematic analysis and development of a conceptual model.SettingVirtual interviews, conducted in British Columbia, Canada.Participants12 field experts, recruited based on their interest and work related to P4 and related concepts.ResultsFour factors were seen as promoting or hindering P4 efforts depending on context: relationship between patient and clinician, education of clinicians and the public, health system design and influencers. We extracted four broad enablers of P4: evidence-based medicine, personal experiences and questioning attitude, public P4 campaigns and experience in resource-poor contexts. There were six barriers: peer pressure between clinicians, awareness and screening campaigns, cognitive biases, cultural factors, complexity of the problem and industry influence.ConclusionsElicited facilitators and impediments to the application of P4 were similar to those seen in existing literature but framed uniquely; our findings place increased emphasis on the clinician–patient relationship as central to decision-making and position other drivers as influencing this relationship. A transition to a model of care that explicitly integrates conscious protection of patients by reducing overtesting, overdiagnosis and overtreatment will require changes across health systems and society.