The Municipal Library Elevator Coup (Portuguese: Golpe do Elevador da Biblioteca), also known as The Elevator Coup (Intentona do Elevador) or 28 January 1908 Coup (Golpe de 28 de Janeiro de 1908), was the name given for the attempted coup d'tat by members of the Portuguese Republican Party and Progressive Dissidency against the administrative dictatorship of Prime Minister Joo Franco (and the political ascendancy of the Liberal Regenerator Party). The event was not confined to the Municipal Library Elevator, but was so named for the arrest of many conspirators at the structure on the afternoon of January 28, 1908. Although the coup was prevented by government forces, it failed to capture all the conspirators, which contributed to the assassination of the monarch Carlos I of Portugal and the heir to the throne, the Prince Royal, Lus Filipe. These events would continue legislative instability and lead to the Portuguese First Republic, the raison d'tre of the coup conspirators.

The Portuguese Republican Party (Portuguese: Partido Republicano Português, pronounced [pɐɾˈtiðu ʁɛpuβliˈkɐnu puɾtuˈɣeʃ]; 1876–1911) was a Portuguese political party formed during the late years of monarchy that proposed and conducted the substitution of the Constitutional Monarchy by the Portuguese First Republic.When the Republic was established on the 5 October 1910 Revolution, the members of the party initially stood together, but soon began splitting into different parties, including the Democratic Party, Democratic Leftwing Republican Party, Reformist Party, Republican Union, Evolutionist Party, Centrist Republican Party, Popular Party, Radical Party, Republican Liberal Party, Liberal Republican Union, Reconstitution Party and Nationalist Republican Party.