Radiotherapy (RT) is an essential and cost-effective cancer treatment. It is underutilised in Australia. Bridging the gap between actual and optimal RT utilisation requires not only provision of adequate RT infrastructure but also an understanding of the factors that influence the extent to which this opportunity for RT is utilised. This study explored factors perceived to affect RT-related decision making by consumers and health professionals (HPs).Six semi-structured focus groups (FGs) and 13 interviews were conducted at three geographical locations in NSW, Australia (n = 26 consumers and 30 HPs). Audio recordings of FGs and interviews were transcribed verbatim and analysed thematically.An exhaustive list of issues perceived to affect consumer and HP RT decisions was identified. There were common themes across participant groups and locations. Perceptions of RT and its benefits, as well as accurate communication of the expected benefits and risks of RT, were highlighted as important to decision making. Perceived factors relating to 'inconvenience' of RT were multifaceted and included travel, relocation, accommodation, time away from work and financial challenges. Perceived potential barriers to RT referral included knowledge of RT and RT services, availability of a local or visiting RT service, referrer bias, and the low profile of RT.Important drivers during RT decisions appear to include the perceived benefit, risks and inconvenience of RT. Underutilisation of RT may also result from multiple barriers at the referrer level. Further research into whether these factors influence actual RT decisions is needed.