| Official Name: | Retalhuleu Department |
| Native Name: | Departmento de Retalhuleu |
| Native Name Lang: | es |
| Settlement Type: | Department of Guatemala |
| Mapsize: | 300 |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location in Guatemala |
| Subdivision Type: | Country |
| Subdivision Name: | Guatemala |
| Seat Type: | Capital |
| Seat: | Retalhuleu |
| Parts Type: | Municipalities |
| Parts: | 9 |
| Government Type: | Departmental |
| Leader Title: | Governor |
| Area Total Km2: | 1856 |
| Population As Of: | 2018 |
| Population Footnotes: | [1] |
| Population Total: | 326828 |
| Population Density Km2: | auto |
| Population Urban: | 187401 |
| Population Blank1 Title: | Ethnicities |
| Population Blank2 Title: | Religions |
| Population Blank2: | Roman Catholicism, Evangelicalism, Maya |
| Utc Offset: | -6 |
| Website: | (in Spanish) |
Retalhuleu (pronounced as /es/) is a department located in the south-west of Guatemala, extending from the mountains to the Pacific Ocean coast. It has an area of 1856 km2. In 2018 the population of the Department of Retalhuleu was 326,828. Its capital, Retalhuleu City, mixes ancient and modern architecture, and it is also known for being a commercial city.
The largest Native American group in the state is the K'iche' (Quiché) Maya people. The department contains a number of Pre-Columbian ruins, including Takalik Abaj, and it also contains numerous amusement parks, the most important and known are Xetulul and Xocomil.
The department is divided into nine municipalities:
Tropical savanna climates have monthly mean temperature above 18 °C (64 °F) in every month of the year and typically a pronounced dry season, with the driest month having precipitation less than 60mm (2.36 in) of precipitation. The Köppen Climate Classification subtype for this climate is "Aw". (Tropical Savanna Climate).[2]