Family-centred care (FCC) has long been acknowledged as best practice for meeting the needs of families of children with hearing loss (HL) and improving early intervention (EI) outcomes. Although the literature has reported some gaps in service provision to families of children with HL, and the period from the time of diagnosis to enrolment in EI has been identified as a significant decision-making period, there is a lack of in-depth knowledge regarding families’ needs during this period. In addition, no study has addressed the current gaps in FCC for children with HL with or without additional disabilities transitioning to EI. Therefore, the overarching aim of this thesis was to develop a family-centred intervention to support families of children with HL transitioning to EI, using an implementation science approach. The specific aims of this thesis were: (1) to explore families’ needs in the transition to EI after diagnosis of HL from both families’ and professionals’ perspectives; (2) to investigate families’ and professionals’ perspectives on the provision of FCC in the transition to EI; and (3) to develop a family-centred intervention for children with HL—with or without additional disabilities—transitioning to EI.Chapter 2 describes the overarching framework applied throughout this thesis, the Behaviour Change Wheel (BCW). The BCW is a step-by-step guide for planning interventions that involves three tasks, including (a) understanding the behaviour that needs to be changed (Chapters 3 and 4), (b) identifying intervention options (Chapter 5), and (c) identifying implementation options and content of the intervention (Chapter 6).Chapter 3 explored families’ needs in the transition to EI using a qualitative approach incorporating semi-structured interviews with families and professionals. Four major themes were identified from the interviews: (1) families require information that meet their specific needs; (2) families require supportive professionals to “walk the journey” with them; (3) some families want to connect with other families who “are in the same boat”; and (4) professional support needs differ for children with HL who have additional disabilities.Chapter 4 investigated families’ and professionals’ perspectives on the implementation of FCC during the transition period. In a convergent mixed-methods study, quantitative data were collected by self-report questionnaires (MPOC-20 and MPOC-SP) and qualitative data by interviews. The results suggested that services provided during the transition period adhered to some of the principles of FCC, including the provision of timely access to EI services and giving emotional and social support. However, areas for improvement included the need to strengthen family/professional partnerships, provide more family-centred training for professionals, and improve shared decision-making processes, program monitoring, and consistency in the provision of information and support.The overarching findings of chapters 3 and 4 indicated that families of children with HL required individualised information and support, and that there was inconsistency in information and services provided to families during the transition period. The research team defined the problem to be addressed as the “provision of individualised information and support to families of children with HL in transition to EI.” To address the problem, the administration of a needs assessment was identified as the behaviour that needed to be changed, with a resource limitation being identified as the main barrier. Thus, the research team developed a Minimum Data Set (MDS) to facilitate a discussion about families’ individual needs during the transition period.Chapter 5 describes a two-round eDelphi study for developing a MDS for assessing the needs of families of children with HL transitioning to EI. Consensus was reached among hearing researchers and professionals on 32 items across six categories, including informational support, professional support, peer support, skills and knowledge, financial support, and methods of information provision. The MDS can be incorporated into a Needs Assessment Tool to support professionals to identify and address families’ unique needs during the transition to EI.To improve the pace of service delivery during the transition period, the provision of eHealth services is recommended in the literature. As the MDS could be delivered online through eHealth or administered in-person, Chapter 6 explored factors influencing the use of eHealth in the context of barriers and facilitators related to capability, opportunity, and motivation. The results indicated that both families’ and professionals’ knowledge of and confidence in using the Internet and technology, as well as families’ access to reliable Internet and affordable equipment, were important factors that influenced the use of eHealth services. Families’ and professionals’ beliefs that there were benefits associated with using eHealth services was also identified as an important facilitator. Professionals’ and families’ preferences and a culture of face-to-face services were identified as barriers for using eHealth interventions.Overall, this thesis has demonstrated that families transitioning to EI following the diagnosis of HL require individualised information and support. The MDS has the potential to facilitate the assessment and management of families’ individual needs during the transition period.