José María Castro Madriz (1 September 1818 – 4 April 1892) was a Costa Rican lawyer, academic, diplomat, and politician.

He was the rector of the national University (which he had helped to create) for sixteen years, and served several administrations as cabinet minister and ambassador.

An active Freemason, Castro was consistently critical of the political influence of the Roman Catholic Church.

He was also a strong defender of freedom of the press at a time when many Costa Rican governments practiced widespread censorship.

As president his lack of a committed political base made him an easy target for overthrow by the military.