| Official Name: | Báč |
| Other Name: | Bacsfa |
| Settlement Type: | village |
| Pushpin Map: | Slovakia |
| Pushpin Label Position: | none |
| Pushpin Mapsize: | 250 |
| Pushpin Relief: | 1 |
| Pushpin Map Caption: | Location of the village |
| Coordinates: | 48.0039°N 17.3767°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Name1: | Trnava |
| Subdivision Type2: | District |
| Subdivision Name2: | Dunajská Streda |
| Established Title: | First written mention |
| Established Date: | 1319 |
| Leader Title: | Mayor |
| Leader Name: | Ildikó Duducz[1] [2] |
| Area Total Km2: | 3.92[3] |
| Elevation M: | 123[4] |
| Population Footnotes: | [5] |
| Population Total: | 560[6] |
| Population Est: | 547 |
| Pop Est As Of: | 2008 |
| Population Density Km2: | 140.96[7] |
| Demographics Type1: | Ethnicity |
| Demographics1 Title1: | Hungarians |
| Demographics1 Info1: | 62,72% |
| Demographics1 Title2: | Slovaks |
| Demographics1 Info2: | 36,22% |
| Timezone: | EET |
| Utc Offset: | +1 |
| Timezone Dst: | EEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postal Code |
| Postal Code: | 931 01 |
| Area Code: | +421 31 |
| Population Density Sq Mi: | 54.42 |
| Area Total Sq Mi: | 1.51 |
| Elevation Ft: | 404 |
Báč (Hungarian: Bacsfa, in Hungarian pronounced as /ˈbɒtʃfɒ/) is a village and municipality in the Dunajská Streda District of the Trnava Region in south-west Slovakia.
In the 9th century, the territory of Báč became part of the Kingdom of Hungary. In historical records the village was first mentioned in 1319. After the Austro-Hungarian army disintegrated in November 1918, Czechoslovak troops occupied the area, later acknowledged internationally by the Treaty of Trianon. Between 1938 and 1945 Báč once more became part of Miklós Horthy's Hungary through the First Vienna Award. From 1945 until the Velvet Divorce, it was part of Czechoslovakia. Since then it has been part of Slovakia.
The municipality lies at an altitude of 126 metres and covers an area of 3.923 km2. It has a population of about 525 people.
The records for genealogical research are available at the state archive in Bratislava (Slovak: Štátny archív v Bratislave)