Caaguazú (Spanish pronunciation: [ka(a)ɣwaˈsu]) is a department in Paraguay. The capital is the city of Coronel Oviedo.

In the 16th and 17th centuries, European settlers in the present-day department of Caaguazú were threatened by the Portuguese Bandeirant and Guaicurú Indians, preventing permanent settlement of the land for many years.

In the 18th century, repopulation of Caaguazu began again. In 1712, Gregorio Bazán de Pedraza founded the Villa de San Isidro Labrador de Curuguaty, followed by Ybytimí in 1715, San Joaquín in 1746, and Carayaó in 1770.

In 1906, the area was assigned the name Yhú, including the departmental capital of Yhú, Ajos (present day Coronel Oviedo), Carayaó, San Joaquín and Caaguazú. Upon territorial reorganization in 1945, it was given the name of Caaguazú.

In 1973, the present-day territory and limits of this department were defined.

Caaguazú is the home department of several Paraguayan personalities, such as the writer Mario Halley Mora and the musician Cayo Sila Godoy.

The name "Caaguazú" (Ka'aguazu in Guaraní) means "great herb."

Caaguazú is located in the middle of the Oriental Region of the country, between latitudes 24º30’ and 25º50’ S and longitudes 55º00’ and 56º45’ W.