The British invasions of the Río de la Plata are a series of unsuccessful British attempts to seize control of the Spanish colonies located around the La Plata Basin in South America (today part of Argentina and Uruguay).

The invasions take place between 1806 and 1807, as part of the Napoleonic Wars, when Spain is an ally of France.

The invasions occur in two phases.

A detachment from the British army occupies Buenos Aires for forty-six days in 1806 before being expelled.

In 1807, a second force occupies Montevideo, remaining for several months, and a third force makes a second attempt to take Buenos Aires.

After several days of street-fighting against the local militia and Spanish colonial army, in which half of the British forces are killed or wounded, the British are forced to withdraw.The social effects of the invasions are among the causes of the May Revolution.

The criollos, who had so far been denied important positions, can now get political strength in military roles.

The successful resistance, with little help from the peninsula, fosters the desire of self-determination.

An open cabildo and the Royal Audience of Buenos Aires deposes the viceroy Rafael de Sobremonte and designates instead the popular hero Santiago de Liniers, which is a completely unprecedented action: before that, the viceroy had only been subject to the King of Spain himself, and no Spanish American had authority over him.