The WHO has called for action to integrate physical activity promotion into healthcare settings, yet there is a lack of consensus on the competencies required by health professionals to deliver effective movement behaviour change support. The objective of this study was to establish key competencies relevant for all health professionals to support individuals to change their movement behaviours. Consensus was obtained using a three-phase Delphi process. Participants with expertise in physical activity and sedentary behaviour were asked to report what knowledge, skills and attributes they believed health professionals should possess in relation to movement behaviour change. Proposed competencies were developed and rated for importance. Participants were asked to indicate agreement for inclusion, with consensus defined as group level agreement of at least 80%. Participants from 11 countries, working in academic (55%), clinical (30%) or combined academic/clinical (13%) roles reached consensus on 11 competencies across 3 rounds (n=40, n=36 and n=34, respectively). Some competencies considered specific to certain disciplines did not qualify for inclusion. Participants agreed that health professionals should recognise, take ownership of, and practise interprofessional collaboration in supporting movement behaviour change; support positive culture around these behaviours; communicate using person-centred approaches that consider determinants, barriers and facilitators of movement behaviours; explain the health impacts of these behaviours; and recognise how their own behaviour influences movement behaviour change support. This consensus defines 11 competencies for health professionals, which may serve as a catalyst for building a culture of advocacy for movement behaviour change across health disciplines.