Radiotherapy is the most commonly used nonsurgical modality in treatment of lung cancers, non–small cell lung cancer (NSCLC) in particular. Radiation therapy has been increasingly used as definitive radical treatment, either alone or in combination with concurrent chemoradiation for locally advanced disease. More recently with the advent of novel radiation techniques and modalities such as stereotactic radiotherapy and proton therapy, radiotherapy can now be used as sole radical treatment of small solitary tumors. This article reviews the current indications and future directions of radiotherapy in lung cancer management.