Treaty of San Ildefonso

Treaty of San Ildefonso may refer to:

• First Treaty of San Ildefonso of 1777 between Spain and Portugal
• Second Treaty of San Ildefonso of 1796 between Spain and France, allying the two nations
• Third Treaty of San Ildefonso of 1800 between Spain and France, by which Spain returned Louisiana to France

See also

• San Ildefonso, a town in central Spain
• Royal Palace of La Granja de San Ildefonso, the summer residence of the Kings of Spain