Serafín Estébanez Calderón (27 December 1799 – 5 February 1867) was a Spanish writer, best known by the pseudonym of El Solitario.

His first literary effort was El listón verde, a poem signed "Safinio" and written to celebrate the revolution of 1820.

He was called to the bar, and settled for some time in Madrid, where he published a volume of verses in 1831 under the assumed name of "El Solitario."

He obtained an exaggerated reputation as an Arabic scholar, and played a minor part in the political movements of his time.

Estébanez Calderón is also the author of an unfinished history, De la conquista y pérdida de Portugal (1883), issued posthumously under the editorship of his nephew, Antonio Cánovas del Castillo.