变应性结膜炎（英语：allergic conjunctivitis，亦称为过敏性结膜炎或变态反应性结膜炎）是结膜的过敏性炎症，虽然症状可能非常明显，但通常不会致盲。

在发达国家，估计过敏性结膜炎的患病率至少在20%以上；和其它过敏性疾病一样，患病率呈上升趋势。以年轻人有为多见，平均起病年龄是20岁，随着年龄增长症状逐步减轻；大约半数的患者并发其它过敏性疾病（如支气管哮喘等），或者具有过敏性疾病家族史。

Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), edema (swelling) of the conjunctiva, itching, and increased lacrimation (production of tears). If this is combined with rhinitis, the condition is termed allergic rhinoconjunctivitis.