Gervasio Antonio de Posadas y Dávila (18 June 1757, in Buenos Aires – 2 July 1833, in Buenos Aires) was a member of Argentina's Second Triumvirate from 19 August 1813 to 31 January 1814, after which he served as Supreme Director until 9 January 1815.
Posadas' early studies were at the convent of San Francisco. Then he studied and practiced law with Manuel José de Labardén. In 1789 Posadas was appointed notary general for the bishopric, and held that post until the events of the May Revolution. He was unaware of the impending revolution and was caught by surprise when the Buenos Aires Cabildo (town hall) was occupied on 25 May 1810; he did not agree that it had been legitimately done. His donations to the Sociedad Patriótica made him an associate of the Saavedrist faction, so the leaders of the riots of 5 April 1811 exiled him to Mendoza. A month later he was appointed solicitor-procurator for the City of Buenos Aires.
Posadas was succeeded in office by his nephew, Carlos María de Alvear, who was removed soon afterwards by a military coup d'état. By August 1815 the whole Alvearista faction was in disgrace and Posadas was jailed. The former Supreme Director spent the next six years in 22 different jails. He began writing his memoirs in 1829.