Margarita Barrientos (born 12 October 1961) is an Argentine activist and founder of Los Piletones Soup Kitchen.

In 1996, she moved to Barrio Los Piletones [es], a disadvantaged quarter in the south of the city of Buenos Aires.

[7] In 1966 they started a soup kitchen, calling it Los Piletones and feeding 15 people, eventually increasing to the provision of 2,700 plates of food per day in 2018.

[7] In February 2018, Barrientos opened a restaurant in an old Underground car parked 200 meters from Los Piletones, with the idea of bringing funds and visibility to the work in the kitchen, and also to teach cooking.

[13]In August 2024, footballer Lionel Messi showed his support by presenting her with a signed jersey to be auctioned at the annual fundraising dinner of the Margarita Barrientos Foundation.