| Ñeembucú Department | |
| Native Name: | Departamento de Ñeembucú |
| Native Name Lang: | es |
| Type: | Department |
| Coordinates: | -26.8667°N -76°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Paraguay |
| Subdivision Type1: | Region |
| Subdivision Name1: | Eastern Region |
| Parts Type: | Largest city |
| Parts Style: | para |
| P1: | Pilar |
| Established Title: | Established |
| Established Date: | 1776 |
| Blank Name Sec1: | Number of Districts |
| Blank Info Sec1: | 16 |
| Seat Type: | Capital |
| Seat: | Pilar |
| Leader Party: | ANR |
| Leader Title: | Governor |
| Leader Name: | Víctor Hugo Fornerón |
| Unit Pref: | Metric |
| Area Total Km2: | 12147 |
| Area Rank: | 10 |
| Population Footnotes: | [1] |
| Population Total: | 76,719 |
| Population As Of: | 2022 census |
| Population Rank: | 16 |
| Population Density Km2: | auto |
| Timezone1: | AST |
| Utc Offset1: | -04 |
| Timezone1 Dst: | ADT |
| Utc Offset1 Dst: | -03 |
| Iso Code: | PY-12 |
Ñeembucú (pronounced as /es/; Guaraní: Ñe'ẽmbuku) is a department located in the south of the Eastern Region of Paraguay. The capital is Pilar. The department is almost entirely rural, and is home to some of the oldest and best-preserved Jesuit ruins, which are located near the town of Humaitá.
The department is divided in 16 districts:
The terrain in Ñeembucú is markedly flat, covered mostly in flat, grassy fields only broken by the occasional wetland swamp or green "monte". Montes, despite their name, are not mountains at all, but patches of dense trees and brush that provide shade to the cattle who graze on the flat plains surrounding them. Almost all of the land in Ñeembucú is used for grazing (cattle, sheep) or other types of agriculture.
To the west, Ñeembucú is limited by the Rio Paraguay and Argentina, to the south by the Rio Paraná and Argentina, to the north by the Central department, and to the east by the departments of Paraguarí and Misiones.
Ñeembucú was the theatre of the second phase of the War of the Triple Alliance. Battles fought there included Tuyutí, Curupaytí, the Boquerón del Sauce and Humaitá.