Locally advanced non-small cell lung cancer (NSCLC) represent approximately one third of patients diagnosed with NSCLC, including stage IIIA (resectable and unresectable), and stage IIIB and IIIC patients. Radiotherapy (RT) plays a major role in the curative and adjuvant treatment of locally advanced NSCLC. RT-based comprehensive therapy achieves a 5-year overall survival of 42.9% for unresectable locally advanced NSCLC. For resectable stage IIIA patients, the value of postoperative RT is challenged. However, plenty of retrospective and real-world studies showed postoperative RT could increase overall survival for patients with high risk of relapse. Given the disease inherent heterogeneity, patients have significantly different outcomes. Moreover, significant differences in conventional diagnosis and treatment of NSCLC, target delineation and RT planning are widely observed across domestic RT institutions, and discrepancies may be found in specific work standards among doctors and physicists. Precise target delineation is an important prerequisite for RT benefits. The National Cancer Quality Control Center formulates the guideline for clinical routine practice, indications, target delineation and treatment plan design in definitive (chemo)RT and adjuvant RT for locally advanced NSCLC by referring to relevant standards at home and abroad, aiming to promote the implementation of standardized RT for NSCLC, facilitate multi-center clinical trials and provide reference for RT institutions in China.