The Paraguayan Legion (Spanish: Legión Paraguaya), was a military unit led by colonels Juan Francisco Decoud and Fernando Iturburu that was formed in Argentina during the Paraguayan War, consisting mainly of Paraguayan exiles and opponents of the Francisco Solano López regime.

Legionnaires dominated the Paraguayan political scene during the liberal period of the first post-war years.

The first Provisional government, the Triumvirate of 1869, included two Legionnaires: José Díaz de Bedoya and Carlos Loizaga.

Other members of the unit would reach the country's presidency over the next few decades, such as Benigno Ferreira and Juan Bautista Egusquiza.

[3] Since then, the word legionario has taken the meaning of traitor in Paraguay, being used in speeches by figures such as Alfredo Stroessner and Juan Manuel Frutos to lambast their political adversaries.