Alfonso de Galarreta Genua,, is a Spanish-born Argentine bishop of the Society of Saint Pius X. Bishop de Galarreta has served as the First Assistant of the Society of Saint Pius X, working under the direction of the Superior General Fr. Davide Pagliarani, since 2018. In addition to this, Bishop de Galaretta has been the President of the SSPX—Vatican Commission since 2009, which directs the Society's correspondence with the Holy See.

The Society of Saint Pius X is a canonically irregular traditionalist Catholic fraternity of priests founded in 1970 by Archbishop Marcel Lefebvre. Lefebvre was a leading traditionalist at the Second Vatican Council with the Coetus Internationalis Patrum and Superior General of the Holy Ghost Fathers until 1968. The society was initially established as a pious union of the Catholic Church with the permission of François Charrière, the Bishop of Lausanne, Geneva and Fribourg in Switzerland.