The Reunification of Brittany or Breton Reunification is a political movement to reunite the Loire-Atlantique department with the administrative region of Brittany, to form the entire cultural and historical region of Brittany. This "reunification" is considered a prerequisite for further Breton autonomy.

Loire-Atlantique is a department in Pays de la Loire on the west coast of France, named after the river Loire and the Atlantic Ocean. It had a population of 1,429,272 in 2019.