Greater Buenos Aires (Spanish: Gran Buenos Aires; GBA) is the urban agglomeration comprising the autonomous city of Buenos Aires and the adjacent 24 partidos (municipalities) over the Province of Buenos Aires. Thus, it does not constitute a single administrative unit. The conurbation spreads south, west and north of Buenos Aires city. To the east, the River Plate serves as a natural boundary.

Urban sprawl, especially between 1945 and 1980, created a vast conurbation of 9,910,282 inhabitants in the 24 conurbated partidos, as of 2010, and a total of 12,801,365 including the City of Buenos Aires, a third of the total population of Argentina.