Élisabeth Leseur (1866–1914) was a French mystic renowned for her spiritual writings and the posthumous conversion of her atheist husband, Félix Leseur. Born into a wealthy Parisian family, she married Félix, a medical doctor and prominent leader of the French anti-clerical, atheistic movement. Despite their differing beliefs, Élisabeth maintained a deep Catholic faith, which she nurtured through prayer, meditation, and charitable works.

Throughout their marriage, Élisabeth faced the challenge of her husband's persistent opposition to her faith. In response, she deepened her spiritual life, documenting her reflections in a personal journal and engaging in extensive correspondence. Her health declined over the years, leading to her death in 1914. After her passing, Félix discovered her spiritual writings, including a prophetic note foretelling his conversion. This revelation profoundly impacted him, leading to his return to the Catholic faith and eventual ordination as a Dominican priest.

Élisabeth's writings, particularly her "Journal et pensées pour chaque jour," have inspired many in their spiritual journeys. Her cause for beatification was opened in 1934, and she currently holds the title of Servant of God.