PURPOSE: To review existing scientific literature on mobile applications (apps) in the field of radiation oncology and to evaluate characteristics of commercially available apps across different platforms. METHODS: A systematic review of the literature for publications presenting apps in the field of radiation oncology was carried out using the PubMed database, Cochrane library, Google Scholar, and annual meetings of major radiation oncology societies. Additionally, the two major marketplaces for apps, App Store and Play Store, were searched for available radiation oncology apps for patients and health care professionals (HCP). RESULTS: A total of 38 original publications which met the inclusion criteria were identified. Within those publications, 32 apps were developed for patients and 6 for HCP. The vast majority of patient apps focused on documenting electronic patient-reported outcomes (ePROs). In the two major marketplaces, 26 apps were found, mainly supporting HCP with dose calculations. CONCLUSION: Apps used in (and for) scientific research in radiation oncology are rarely available for patients and HCP in common marketplaces.