Respite and permanent transition to residential aged care are processes that are designed to support preferences and needs of people living with dementia and their carers as the disease progresses. These services are highly variable in acceptability, accessibility, and availability for the caregiving dyad, often not reflecting a person-centred, co-ordinated and cohesive approach. This study aimed to use a two-phase realist synthesis to explore how respite and permanent transition models of care work in different contexts, through different mechanisms to produce varying outcomes. Phase 1 explored preliminary theories and assumptions of the respite care journey, including (a) identification of systematic reviews and innovative programs, and (b) semi-structured interviews sessions with key stakeholders. Phase 2 involved an iterative scoping review to identify and map the available evidence, with a synthesis designed to unpack underlying program theories of why, for whom and in what circumstances respite/transition models of care works. Phase 1(a) identified ten citations from 126 systematic review abstracts. Fourteen residential care managers participated in a contextual scan – Phase 1(b). Phase 2 expanded this knowledge, identifying a further 13 studies. Three program theories, at the macro, meso and micro level, were elucidated: (1) system-level evidence-based integration, through collaboration and co-ordination; (2) inclusive, quality care, with supportive environmental design; and (3) trust, autonomy, and meaning-making. A novel realist synthesis approach was used to explore respite and permanent transition models of care beyond ‘what works’. Importantly, findings at the macro, meso and micro level context, suggest nuance, with a shared decision-making approach, is needed to optimise the ever-changing dementia care journey.