Background The i‐THRIVE Programme is a needs‐based model of care, based on the THRIVE Framework, that is being implemented across the United Kingdom with the aim of improving outcomes for children and young people's mental health and wellbeing. This study aimed to investigate the impact that this programme has on accessibility and quality of care, as viewed by key stakeholders. Methods Interviews with professionals and service users were conducted during the implementation of the THRIVE Framework in four sites of one mental health and community service provider. Results Three themes are identified: ‘impact of needs‐based groupings on referral’, ‘impact of collaborative and interagency approach’ and ‘impact of i‐THRIVE on clinical practice’. Findings suggest that accessibility was seen to be promoted through the integration of a needs‐based approach, flexible re‐referral, signposting and information sharing, the use of goal‐orientated interventions and collaboration over risk and treatment endings. Shared decision making was perceived to improve the experience of care for young people, as was interagency working. Goal‐focused interventions and upfront discussion of treatment endings were seen to help clinicians manage expectations and discharge but could also compromise effectiveness and engagement. Obstacles to impact were resistance to interagency working and a shortage of resources across the system. Conclusions i‐THRIVE is a promising approach with the potential to facilitate the accessibility and quality of mental health care. However, a tension exists between enhancing accessibility and quality of care, which points towards the importance of outcome and satisfaction monitoring. Obstacles to impact point to the importance of a whole‐system approach supported by sufficient resources across the locality.