Feliksa Kozlowska (also known as Felicja Kozlowska and Sister Maria Franciszka) (May 27, 1862, Wieliczna - August 23, 1921, Płock) was a Polish religious mystic and visionary who founded what eventually became the Old Catholic Mariavite Church, and, by implication, a dissident group which split from it in 1935, the Catholic Mariavite Church. Both groups had their origin from the Roman Catholic Church, which considered both heretical.