Movimiento al Socialismo

The Movement for Socialism – Political Instrument for the Sovereignty of the Peoples (Spanish: Movimiento al Socialismo ^ⓘ – Instrumento Político por la Soberanía de los Pueblos; MAS or MAS-IPSP) is a socialist political party in Bolivia. Its followers are known as Masistas.

In the December 2005 election, MAS-IPSP won the first majority victory ever won by a single Bolivian party since Bolivia's return to democracy, electing Evo Morales as president. The party went on to win the next four general elections by a majority, ruling until 2025, when their support collapsed during that year's election. MAS–IPSP also dominated the municipal elections during this period.

MAS-IPSP evolved out of the movement to defend the interests of coca growers and is rooted in indigenous mobilization. Morales has articulated the goals of his party and popular organizations as the need to achieve plurinational unity, and to develop a new hydrocarbon law which guarantees 50% of revenue to Bolivia, although political leaders of MAS-IPSP in later years showed interest in complete nationalization of the fossil fuel industries, as well as the country's lithium deposits.

During Arce's government, the party was divided into two internal factions: the "Arcistas" (Renovator Bloc), which defends Luis Arce's management and seeks the renovation of the party leadership, which is chaired by Grover García, and the "Evistas", which defends Morales's leadership and seeks his re-election in the 2025 Bolivian general election. On 4 October 2023, President Luis Arce and Vice President David Choquehuanca were expelled from the party by a decision of the board chaired by Evo Morales. However, the Arcista faction did not recognize the expulsion.

By February 2025, Morales left MAS due to the party prohibiting him from running for president in the 2025 general election; initially joining the Front for Victory party, he and his supporters later went on to found a new party, EVO Pueblo.