The underutilisation of radiation therapy (RT) is contributing to the significant global burden of cancer with studies identifying actual utilisation rates are significantly lower than evidence-based optimal utilisation rates. Attributing factors vary considerably, ranging from patient preference, referrer bias, to geographic variations. The aim of this scoping review is to map and synthesise the current literature reporting on barriers and facilitators influencing utilisation of RT globally. Four online databases; Medline, Embase, Scopus and CINAHL identified articles dated between 1993 and 2023. Study eligibility included reporting on RT services, specifically barriers and influences on utilisation of RT. Title and abstract screening, followed by full text review was performed as per PRISMA guidelines. Variables were extracted and categorised into patient, health professional (HP) and department level influences. In total, 340 studies were included in the scoping review. HP influences (included in this specific review) were reported in 225 (66 %) papers with the most prevalent HP influence being referral (n = 187; 83 %). Of the HP papers, 114 (51 %) identified knowledge and education as an influence on RT utilisation. Subsequently, role interpretation, describing the assumed role adopted by the General Practitioner as the patients advocate, educator, manager or carer was identified in 89 (40 %) studies. This scoping review demonstrates the range of factors impacting RT utilisation. The results suggest referrer knowledge and understanding gaps impact RT utilisation internationally. Future research and intervention into referrer RT education is required to limit the impact of such influences.