Gabriel Vásquez SJ (1549 or 1551 in Belmonte, Cuenca – 23 September 1604 in Alcalá de Henares), known as Bellomontanus, was a Spanish Jesuit theologian and scholastic philosopher.

Vásquez was the foremost academic rival of his fellow Jesuit Francisco Suárez, whose philosophical views he often and openly criticized.

On 30 July 1585, Claudio Acquaviva, then general of the Jesuits, summoned him to Rome to replace Francisco Suárez as professor of Theology in the Roman College, now the Gregorian University.

He was, with Suárez and Blas Diego, a member of the commission set up by the Provincial Congregation of Toledo held at the College of Alcalá in 1593 to evaluate the theological and philosophical sections of the Ratio Studiorum of 1586.

We learn from a letter of Luis de Molina to Acquaviva that Vásquez was a member of the commission set up to examine the Spanish Index of Prohibited Books and to indicate the necessary emendations.

In him, according to the 19th-century German Redemptorist writer Michael Haringer, virtue competed with doctrine, obedience with genius, and piety with learning.

[5] The Duke of Lerma, favourite of Philip III of Spain, frequently consulted him in the most important matters, and Benedict XIV called him the luminary of theology.

The 1913 Catholic Encyclopedia describes Vásquez as "immensely influential", praising his clear writing and strict method.

Vernon Bourke credits him as the probable source of Descartes's mind-body dualism and of Immanuel Kant's argument from morality.