As the prognosis of lung cancer patients improves, more patients are at risk of developing local recurrence or a new primary tumour in previously irradiated areas. Technological advances in radiotherapy and imaging have made treatment of patients with high-dose re-irradiation possible, with the aim of long-term disease-free survival and even cure. However, high-dose re-irradiation with overlapping volumes of previously irradiated tissues is not without risks. Late, irreversible, and potentially serious normal tissue damage may occur because of injury to surrounding thoracic structures and organs at risk. In this Review, we aimed to report the efficacy and toxic effects of high-dose re-irradiation for locoregional recurrent non-small-cell lung cancer. Our findings indicate that high-dose re-irradiation might be beneficial in selected patients; however, patients and physicians should be aware of the scarcity of high-quality data when considering this treatment.