Although current recommendations for the treatment of advanced non-small cell lung cancer (NSCLC) include a maximum of six cycles of platinum-based combination therapy as a first-line approach, most patients experience progression within 3–4 months. Therefore, a new treatment strategy, maintenance therapy, has been proposed, and several large randomized prospective controlled trials have shown benefits with maintenance therapy. Maintenance therapy can be classified as either continuation maintenance, which is defined as a prolongation of a part of the first-line chemotherapy or molecularly targeted agent until progression, or switch-maintenance, which is defined as the administration of a different cytotoxic chemotherapy or molecularly targeted agent immediately after induction therapy. In this article, recent results from large randomized phase III trials regarding maintenance therapy are reviewed in order to evaluate the role of maintenance therapy in NSCLC.