Stage IIIA non-small cell lung cancer (NSCLC) consists of a heterogeneous group of disease, ranging from small T1a tumours with ipsilateral mediastinal lymph node involvement over T3 tumours with chest wall invasion, up to T4 tumours with mediastinal invasion with or without positive hilar lymph nodes. Based on this heterogeneity, treatment approaches as well as prognosis are very dependent on specific subgroups. Therapy recommendations should be based on multidisciplinary case discussions in high volume centres including medical and radiation oncologists, pneumologists and experienced thoracic surgeons specialized in thoracic cancer surgery. Recommendations may differ from standards in highly selected cases.Therefore, independent of age, in medically fit (operable) patients with resectable stage IIIA tumours, an aggressive approach in a curative setting is key to obtain good overall survival rates. Moreover, maintaining quality of life is essential. In this narrative review the different aspects of all the subgroups of stage IIIA NSCLC and their heterogeneity as well as the variety of treatment modalities, their combined treatment approaches and survival rates are discussed. Again, the reported 5-year survival rates, ranging from 5% in patients with bulky N2 disease, up to 50% for patients with superior sulcus tumours with hilar lymph node disease, reflect the heterogeneity of stage IIIA NSCLC.