Movimiento Unión Soberanista (MUS) is a Puerto Rican political movement. The movement was founded in November 2010 in the city of Caguas, PR. They are presently attempting to get 60,000 endorsements required by the new electoral law of the Commonwealth to enroll in the State Elections Commission (CEE).

The Movement operates out of its central headquarters at 656 Ave. Ponce de Leon in Hato Rey were volunteers currently work to achieve the inscription before the start of the 2012 electoral year. The main aspiration of the MUS is to build a New Puerto Rico unifying different ideological tendencies on the question of the island's political status through a national claim of sovereignty, an indispensable requirement towards an international law-backed decolonization process to end Puerto Rico's 500 plus years as a colonial dependency. The MUS wants to be a real opposition to the worn-off, highly criticized local majority parties, NPP (currently holding office) and the PDP, by organizing a better and honest government fully compromised with a long-needed social justice programme for all Puerto Ricans.

Currently, the MUS is on a island-wide inscription rally to finish the drive to complete the less of 25,000 endorsements left to complete the inscription.

It is the political wing of the "Instituto Soberanista Puertorriqueño".