The Centenary March or Centenary March of the Great Union was a civic demonstration organized by George Simion and various non-governmental organizations from Romania and Moldova, known under the collective name "Alliance for the Centenary". It started in Alba Iulia (Romania) on 1 July 2018 and ended in Chișinău (Moldova) on 1 September 2018. Its participants, both Moldovans and Romanians, targeted 300 cities and villages, passing through several points significant for the Great Union.

George Nicolae Simion is a Romanian right-wing politician and civic activist. He is the president of the Alliance for the Union of Romanians (AUR), a Romanian political party that gained prominence after its unexpectedly strong showing in the 2020 Romanian legislative election.