| Official Name: | Zasavica I |
| Settlement Type: | Village (Selo) |
| Pushpin Map: | Serbia Vojvodina#Serbia#Europe |
| Pushpin Label Position: | bottom |
| Subdivision Type: | Country |
| Subdivision Name: |  Serbia |
| Subdivision Type1: | Province |
| Subdivision Type2: | Region |
| Subdivision Name2: | Mačva |
| Subdivision Type3: | District |
| Subdivision Name3: | Srem |
| Subdivision Type4: | Municipality |
| Subdivision Name4: | Sremska Mitrovica |
| Unit Pref: | Metric |
| Population As Of: | 2011 |
| Population Total: | 772 |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Coordinates: | 44.952°N 19.503°W |
Zasavica I, also known as Zasavica (Serbian: Засавица) or Gornja Zasavica (Serbian: Горња Засавица), is a village in the Sremska Mitrovica municipality, in Serbian province of Vojvodina. The village has a Serb ethnic majority and its population numbering 772 people (2011 census).
The village is located 12 km south-west of Sremska Mitrovica, on the river Zasavica. Although part of the Srem District, Zasavica I is situated in the region of Mačva south of the Sava river. It is one of several settlements in the northern section of the region of Mačva which were administratively included into the province of Vojvodina when it was created in 1945. With the adjacent village of Zasavica II (Donja Zasavica), it still forms a single cadastral unit, although they are treated as separate villages for census purposes.