BACKGROUND: Despite repeated calls to action and considerable attention, childhood vaccination uptake has declined for a thirteenth consecutive year in the United Kingdom (UK). Increasingly, stakeholders are advocating for research which goes beyond vaccine hesitancy and explores service accessibility in greater depth. This scoping review aims to identify and critically assess how accessibility is being conceptualised and investigated with a view to informing future research. Research, that in turn, will dictate the interventions pursued to improve vaccination coverage. METHODS: A detailed search strategy was implemented across seven databases to identify research exploring parents' experiences of accessing childhood vaccination services within the UK. The analysis explored the studies in relation to their conceptualisation of access, methodology, reported results, and recommendations for research or practice using a combination of descriptive qualitative content analysis, typologies, and frequency counts. Methods and reporting adhered to the 'JBI Manual for Evidence Synthesis' and the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews'. RESULTS: Forty-five studies were included in the analysis. Studies claimed to consider only attitudinal constructs (4%) or did not discuss access at all (33%) despite findings, in part, including access related issues. Remaining studies used the term access in passing or ambiguously (24%), distinguished between attitudes and access in-text (27%), and a minority of studies utilised a theoretical framework which acknowledged accessibility (13%). The focus on access to information (92% of studies) was disproportionately large compared to other domains of accessibility such as availability (11%), affordability (13%), and proximity (16%). Of the seven identified intervention studies, five were centred on information provision. CONCLUSION: Accessibility is poorly conceptualised within most of the research conducted on childhood immunisation uptake within the UK. This, in part, is because exploring accessibility was not an explicit objective of many of the studies included in the review. It is vital that the accessibility of childhood vaccination services is given greater priority and appropriately defined in empirical research. Otherwise, researchers run the risk of limiting the scope of their findings based on their own conceptual ideas regarding the drivers of poor uptake rather than the lived reality of parents.