Santo Antônio da Barra is a municipality in southwest Goiás state, Brazil.

Santo Antônio is 190 kilometers from the state capital, Goiânia and is part of the Sudoeste de Goiás Microregion.

Santo Antônio da Barra is bathed by a vast river network, formed by the Verdão, which separates the municipality from Acreúna and Paraúna; Verdinho, on the border with Rio Verde; and Ribeirão Lage, which forms the boundary with Santa Helena de Goiás.

In 1963 the settlement was elevated to the status of district of Rio Verde The first municipal school, Escola Municipal Antônio Gouvêia de Morais, was built in 1976 with the secondary school, Irmãos Messias da Costa, being built in 1983.

The economy is based on subsistence agriculture, cattle raising, services, public administration, and small transformation industries.