José María de Achá Valiente (8 July 1810, Cochabamba – 29 January 1868) was a military general and president of Bolivia (1861–64). He served in the battles of the Peru-Bolivian Confederation and conspired against longtime dictator Manuel Belzu (1848–55). Later, he was appointed Minister of war in the cabinet of another dictator, José María Linares (1857–61). In that capacity, he led the 1861 coup d'état that toppled Linares. Originally he governed as head of Junta, and then as sole leader of the revolutionary government.
At first, Achá was quite popular by virtue of having ended the hated Linares' tyrannical rule. He extended a political amnesty, and legitimized his rule by winning the 1862 elections. Soon, however, he was plagued by rebellions, the bane of any Bolivian president during this chaotic period. At that point, Achá invoked a state of emergency and began to suppress civil liberties. In particular, he became unpopular as a result of the 1862 "Matanzas de Yáñez" (Yáñez Bloodbath), when the Achá supporter and military governor of La Paz Province, Plácido Yáñez, massacred dozens of opposition figures, many of them from the pro-Belzu camp. Among those murdered was former president Jorge Córdova. Eventually, discontent became widespread, and Achá found it difficult to govern at all. Indeed, parts of the party were controlled by different caudillos and military warlords. The president was finally overthrown in an 1864 coup d'état led by General Mariano Melgarejo, who would go on to become the most ruthless and brutal dictator of 19th-century Bolivia.
After a couple of years in exile, the broken and unpopular Achá returned to Bolivia, where his safety was guaranteed by the now consolidated regime of General Melgarejo. Confined to his home city of Cochabamba, the ailing former President died there in 1868, less than 4 years after being overthrown. He was 57 years old.