Events from the year 1940 in Argentina
- Buenos Aires Province: Aurelio Amodeo (until 7 March); vacant thereafter (starting 7 March)
- President Ortiz takes leave from work because of diabetes
- Construction of the first airplane made in Argentina, a curtiss 75
- Ortiz, during his leave from work, offers his resignation to the Congress amid a political controversy. The Congress does not accept it.
- The Congress discusses a proposal for economic reactivation made by minister Federico Pinedo
- Radio El Mundo starts the radio drama Los Pérez García, which would last up to 1969
- Argentina keeps a neutral stance in World War II, amid foreign pressure to join the war
- April 9 - Chunchuna Villafañe, model, actress and architect
- April 30 - Ermindo Onega, footballer (died 1979)
- May 15 - Carlos Bielicki, chess master
- July 7 - Dora Baret, actress
- August 17 - Eduardo Mignogna, film director and screenwriter (died 2006)
- September 24 - Amelita Baltar, tango singer
- October 17 - Carlos Heller, executive, cooperative banking leader, and politician
- November 18 - Susana Ruiz Cerutti, lawyer and politician (died 2024)
- date unknown
- Esther Norma Arrostito
- Graciela Paraskevaidis
- Guillermo José Garlatti
- Guillermo Saucedo
- Gustavo Bergalli
- Horacio Usandizaga
- Jesús Taboada
- Jorge Ginarte
- Jorge Kissling
- José Rubinstein
- Juan Carlos Maccarone
- Juan Paletta
- Juan Rosai
- Leonardo Henrichsen
- Luis Brandoni
- Luis Cubilla
- Maria Teresa Luengo
- Mario Acuña
- María Cristina Laurenz
- Miguel Ángel Loayza
- Nacha Guevara
- Nestor Combin
- Osvaldo Lamborghini
- Osvaldo Álvarez Guerrero
- Raúl Zaffaroni
- Roberto Matosas
- Rodolfo Mederos
- Román Quinos
- Silvio Marzolini
- Wálter Machado da Silva