Saint Louis Martin (1823–1894) was a French layman and the father of Saint Thérèse of Lisieux, one of the Catholic Church’s most beloved saints. Born on August 22, 1823, in Bordeaux, France, Louis aspired to join the religious life but instead became a successful watchmaker. In 1858, he married Zélie Guérin, a skilled lacemaker. Together, they built a deeply spiritual family, raising nine children, five of whom entered religious life, including Thérèse, who became a Doctor of the Church.

Louis was a devoted husband and father, guiding his family with faith, love, and humility. After Zélie's death in 1877, Louis dedicated himself entirely to his daughters, supporting Thérèse in her early calling to join the Carmel at the age of 15. Despite enduring health struggles, including a debilitating stroke in his later years, he remained a model of perseverance and trust in God.

Pope Benedict XVI beatified Louis and Zélie Martin together on October 19, 2008, and Pope Francis canonized them on October 18, 2015, as the first married couple to be declared saints together. Their feast day is celebrated on July 12. At their canonization, Pope Francis highlighted their example of "faithful love and generous service to life," making them an enduring model for Christian families.