The Society of St. Pius X was founded in 1970 by Archbishop Marcel Lefebvre (1905-1991) in reaction to the reforms of the Second Vatican Council.  These reforms included the substitution of a vernacular Mass for the traditional Latin Mass and a new emphasis on interfaith dialogue.  Most important to the priests of SSPX was the celebration of the traditional Latin Mass, but SSPX also stood against other "modernist" trends, including the Church's ecumenical dialogue with non-Catholic groups, and specifically efforts to improve relations with the Jewish community.

In 1988 SSPX's founder, Archbishop Marcel Lefebvre, consecrated four priests as bishops without Vatican approval; he and the priests were consequently excommunicated by the Church.  When Lefebvre died in 1991 the four priests, Bernard Fellay, Bernard Tissier de Mallerais, Richard Williamson and Alfonso de Galarreta, continued to champion SSPX positions, along with a constellation of like-minded organizations and independent traditionalist Catholics.  Bishop Bernard Fellay currently runs SSPX from its headquarters in Switzerland.

In 2007, Pope Benedict XVI issued a directive that allowed the Latin (Tridentine) Mass to be celebrated in certain circumstances, thereby narrowing the theological distance between SSPX and the Vatican.  In January 2009 the Vatican lifted the excommunication of the four SSPX bishops.

In the United States, SSPX claims about 100 chapels and 24 schools.  Its U.S. monthly periodical, The Angelus, has about 3,000 subscribers.  It also maintains a Web site.