Accelerator physics is an interdisciplinary topic of applied physics, commonly defined by the intent of designing, building and operating particle accelerators. As such, it may be roughly circumscribed as the study of motion, manipulation and observation of relativistic charged particle beams and their interaction with an accelerator structure by electromagnetic fields.

The experiments conducted with particle accelerators are not regarded as part of accelerator physics, but belong to their respective fields of interest (particle physics, condensed matter physics etc.).