Rancho Viejo is a town in Cameron County, Texas, United States.

As of the 2020 United States census, there were 2,838 people, 1,023 households, and 779 families residing in the town.

About half of Rancho Viejo is served by the Brownsville Independent School District.

The other half is served by the Los Fresnos Consolidated Independent School District.

Rancho Viejo is also the name of the resort and country club that takes up much of the space in the town.