Non-small-cell lung cancer is one of the most common malignant tumors worldwide. The majority of patients are not treatable with curative intent because of the extent of disease or patient comorbidity. Radiotherapy to the primary intrathoracic tumor is used with the aim of palliating troublesome local symptoms in approximately 25% of patients. The dose/fractionation regimens used evolved empirically, and surveys have shown widespread variation. It has not yet been clearly established which regimens give the most benefit and least toxicity. This systematic review identified 12 randomized controlled trials comparing palliative external beam radiotherapy regimens. Narrative synthesis has been performed. Palliative radiotherapy is effective in controlling symptoms. There is no strong evidence that better palliation is obtained with higher radiation doses but good evidence that toxicity is greater. There is evidence of a modest survival benefit with higher dose schedules in patients with good performance status. The majority of patients should receive short courses (one or two fractions) of hypofractionated radiotherapy, Selected patients with good performance status should be considered for higher dose regimens if the chance of modest improvement in survival and palliation is considered worth the additional inconvenience and toxicity.