| Municipality of Šempeter-Vrtojba | |
| Native Name: | Občina Šempeter - Vrtojba |
| Native Name Lang: | sl |
| Settlement Type: | Municipality |
| Coordinates: | 45.9167°N 52°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Traditional region |
| Subdivision Name1: | Littoral |
| Subdivision Type2: | Statistical region |
| Subdivision Name2: | Gorizia |
| Leader Title: | Mayor |
| Leader Name: | Milan Turk (SLS) |
| Unit Pref: | Metric |
| Area Total Km2: | 15.0 |
| Population Footnotes: | [1] |
| Population Total: | 6292 |
| Population As Of: | 2021 |
| Population Density Km2: | auto |
| Timezone1: | CET |
| Utc Offset1: | +01 |
| Timezone1 Dst: | CEST |
| Utc Offset1 Dst: | +02 |
The Municipality of Šempeter-Vrtojba (in Slovenian pronounced as /ʃɛmˈpeːtəɾ ʋəɾˈtoːjba/ or in Slovenian pronounced as /ʃəmˈpeːtəɾ ʋəɾˈtoːjba/; Slovenian: Občina Šempeter - Vrtojba; Italian: Comune di San Pietro-Vertoiba) is a municipality in Slovenia. The municipality comprises the town and municipal seat of Šempeter pri Gorici and the adjacent village of Vrtojba. It borders Italy.
Both settlements used to be suburbs of town of Gorizia until 1947, when they become part of Yugoslavia while Gorizia remained a part of Italy. They have had a separate urban development since then. Nowadays, the Municipality of Šempeter-Vrtojba forms a single continuous urban area with the neighbouring towns of Nova Gorica and Gorizia.[2] Since May 2011, these three municipalities have been joined in a common trans-border metropolitan zone, administered by a joint administration board.[3]