Stereotactic body radiotherapy (SBRT) was first described in the mid 90s as a technique using high precision radiotherapy to deliver escalated, ablative irradiation doses and which simultaneously minimised incidental irradiation of healthy tissue. Technological and clinical development of this technique has been pioneered in the field of early stage non-small cell lung cancer, where improved local tumor control led to prolonged overall survival. Today, SBRT is the evidence-based and guideline-recommended treatment of choice for early stage NSCLC in patients who are medically inoperable. SBRT has been demonstrated to be a safe and effective curative treatment option, even for very elderly patients and patients with severe comorbidities. Only patients with very short survival expectancy should not be offered SBRT. Increasing evidence suggests that the outcome is similar or equivalent for surgical lobectomy and SBRT in operable patients; however, SBRT is currently only recommended for patients refusing surgical resection. Many clinical trials are currently evaluating the value of SBRT in clinical settings other than early stage NSCLC, e.g. oligometastases and oligoprogression.