Louis Montoya (1497-1569) was an Augustinian friar and writer noted for his personal austerity and prayerful life, as well as for reforming the Order of Saint Augustine in Portugal.

Louis was born in 1497 in Belmonte, Cuenca, Spain. Having gone to Salamanca to study law, Louis joined the Augustinian Order in 1514.

He was only 24 years old when he was named Director of Novices in Salamanca. Saint Thomas of Villanova was Prior (local superior) at the time. Saint Alfonso de Orozco, John the Baptist Moya and Augustine de Coruña are numbered among the Novices whom Louis helped to form.

The Augustinian Prior General (world leader) sent Louis to Portugal in 1525 with a mandate to reform Augustinian life there. He served as Director of Novices and Prior.

By personal example and wise leadership, Louis was instrumental in restoring strict religious observance, proper discipline and a spirit of prayer in the Order. So notable was this change that the Portuguese Jesuits decided to send their candidates to the Augustinian school so that they would be instructed in prayer and meditation.

Louis was nominated to be Bishop of Viseo. But no amount of persuasion could persuade Louis to accept episcopal ordination.

He wrote many spiritual books. His reputation as a humble and austere religious grew. A year before Louis died, Jerónimo Román wrote,

The religious priest Louis Montoya, ... throughout his long life has never grown tired of doing penance and living the austere life as he has always done.

He died in 1569. In the register of deaths appears the notation that Louis "governed the Province of Portugal in a most holy way."

His remains are preserved at Our Lady of Grace Church, Lisbon.