Kirchnerism ( Spanish: kirchnerismo) is an Argentinian political group formed by the supporters of the late Néstor Kirchner, president of Argentina from 2003 to 2007, and of his wife Cristina Fernández de Kirchner, president from 2007 until 2015. Although the Kirchners are members of the Justicialist Party (the original, official and largest Peronist party, founded by Juan Perón in 1947), Peronism itself is a broad movement, and many Peronists oppose them ("Anti-Kirchnerist Peronism").
Kircherism is generally considered to fall into the category of left-wing populism.
Kirchnerism, although originally a faction in the Justicialist Party, later received support from other smaller Argentine political parties (like the Communist Party or the Humanist Party), and from factions of some traditional parties (like the Radical Civic Union and the Socialist Party). In parties which are divided along Kirchnerist/Anti-Kirchnerist lines, the members of the Kirchnerist faction are often distinguished with the letter K (for instance "peronistas/justicialistas K", "radicales K" or "socialistas K"), while the factions opposing kirchnerism are similarly labeled with the expression Anti-K.
In response to the rise of Kirchnerism, the term "Anti-Kirchnerism" has arisen to describe those sectors and persons, as much within as without Peronism, who opposed the governments of Néstor Kirchner and Cristina Fernández.