The National Basilica of the Sacred Heart is a Roman Catholic minor basilica and parish church in Brussels, Belgium. It is dedicated to the Sacred Heart, inspired by the Basilique du Sacré-Coeur in Paris. Symbolically, King Leopold II laid the first stone in 1905 during the celebrations of the 75th anniversary of Belgian independence. The construction was halted by the two World Wars and finished only in 1970. Belonging to the Metropolitan Archdiocese of Mechelen–Brussels, it is one of the largest churches by area in the world.

Basilicas are Catholic church buildings that have a designation, conferring special privileges, given by the Pope. Basilicas are distinguished for ceremonial purposes from other churches. The building need not be a basilica in the architectural sense. Basilicas are either major basilicas, of which there are four, all in the Diocese of Rome, or minor basilicas, of which there were 1,810 worldwide as of 2019.