Lymphomas are lymphoproliferative malignancies that frequently involve intrathoracic structures. Although their primary presentation is typically nodal, pleural involvement is not uncommon and may manifest as pleural effusions. These effusions can be malignant, due to direct neoplastic infiltration, or benign, secondary to a nonneoplastic process such as lymphatic obstruction or inflammation. Pleural effusion occurs more often in association with non-Hodgkin lymphoma than with Hodgkin lymphoma. Moreover, lymphoma-associated pleural effusion represents one of the most frequent causes of chylothorax, a characteristic milky-white pleural effusion resulting from disruption or obstruction of the thoracic duct. Unlike pleural effusions from most other malignancies, those associated with lymphoma often carry a more favorable prognosis, reflecting the high responsiveness of the effusion to treatment of the underlying lymphomatous disease.