Abstract Background The number of older adults accessing the healthcare service far exceeds the available geriatric specialist services. It is recognised that for the foreseeable future most hospital inpatient contacts with older adults will be completed by doctors not specifically trained in geriatric medicine. To ensure the provision of adequate healthcare, it is imperative that that all hospital doctors are trained in the minimum geriatric competencies. Allowing for the broad, complex, and multidisciplinary nature of geriatric medicine, we conducted a group concept mapping (GCM) study to permit multiple stakeholders with various expertise to convey their thoughts on the competencies required by all hospital doctors caring for older adults. Methods GCM is a mixed methods approach utilising six phases to generate expert group consensus, enabling participants to organise and represent their ideas. We invited healthcare professionals, patient advocacy groups and clinical educators to participate in GCM via an online platform. Hierarchical cluster analysis and multi-dimensional scaling were utilised to analyse participant input regarding competencies required by doctors caring for older adults. Results Forty-eight participants completed the brainstorming stage, generating eighty-eight statements, and twenty-two participants took part in the subsequent sorting stage. Participants included hospital doctors, general practitioners, allied health professionals and patient advocacy groups. Nine competency domains were identified as integral for all hospital doctors to care for older adults. Domains rated most important related to interpersonal communication skills, ethical and legal matters relating to older adults, recognition and management of delirium and medication management. Conclusion The twelve competency domains indicate the diverse skillset required by all doctors to provide comprehensive care to older adults within a hospital setting. This study identifies competencies that may serve as a foundational framework for ensuring quality healthcare for the ageing population. Future initiatives should consider incorporating these competencies to improve inpatient care provided by hospital doctors to older adults.