Primary neuroendocrine neoplasms of the lung represent a clinical spectrum of tumors ranging from the relatively benign and slow-growing typical carcinoid to the highly aggressive small-cell lung carcinoma. The rarity of carcinoids has made the role of radiation therapy in their management controversial. This review considers the results of published studies to generate treatment recommendations and identify areas for future research. Surgery remains the standard of care for medically operable disease. Histology plays the most important role in determining the role of adjuvant radiation. Resected typical carcinoids likely do not require adjuvant therapy irrespective of nodal status. Resected atypical carcinoids and large-cell neuroendocrine carcinomas have a significant risk of local failure, for which adjuvant radiation likely improves local control. Definitive radiation is warranted in unresectable disease. Palliative radiation for symptomatic lesions has demonstrated efficacy for all histologies. Collaborative group trials are warranted.