Louis Gaston Adrien de Ségur (April 15, 1820 – June 9, 1881) was a French bishop and charitable pioneer.
de Ségur became a prelate of the papal court, and canon-bishop of Saint-Denis.
In 1881 he organized the first formal Eucharistic Congress in Lille France which was approved by Pope Leo XIII and was attended by 40,000 people.