Modesto Omiste is a province in the south of the Bolivian Potosí Department.

The province is named after the Bolivian writer and politician Modesto Omiste Tinajeros.

In the north it borders Sud Chichas Province, in the east Tarija Department, in the south and south-west the Republic of Argentina.

It was named after the Bolivian president Eliodoro Villazón The province is further subdivided into cantons (cantones): The main language of the province is Spanish, spoken by 97%, while 44% of the population speak Quechua.

18% of the population are employed in agriculture, 11% in industry, 71% in general services.