Nicasio Álvarez de Cienfuegos (14 December 1764 - 1809) was a Spanish poet and publicist.

He was born at Madrid, and studied with distinction at Salamanca, where he met the poet Melendez Valdés . His poems, published in ??, immediately attracted attention. He was successively editor of the Gaceta and Mercurio, and was condemned to death for having published an article against Napoleon; on the petition of his friends, he was respited and deported to France; he died at Orthez early in the following year.

His verses are modelled on those of Melendez Valdés; though not deficient in technique or passion, they are often disfigured by spurious sentimentality and by the flimsy philosophy of the age. Cienfuegos was blamed for an unsparing use of both archaisms and gallicisms. His plays, Pilaco, Zoraida, La Condesa de Castilla and Idomeneo, four tragedies on the pseudo-classic French model, and Las Hermanas generosas, a comedy, are mostly forgotten.