Tafí Viejo is a town in Tucumán Province, Argentina. It lies about 15 kilometres (9 miles) north of the provincial capital, San Miguel de Tucumán, just west of National Route 9. It forms part of the capital's metropolitan area and functions as an important suburb of the larger city.
At the 2001 census, conducted by Argentina's national statistics institute (INDEC), the municipality had a population of 48,459 inhabitants. That figure reflects the town's role within the densely settled corridor around San Miguel de Tucumán.
Its position on National Route 9, a major north–south artery through the province, places Tafí Viejo directly along one of the region's principal transport links and within easy reach of the capital.