| Vianen | |
| Settlement Type: | City and former municipality |
| Flag Size: | 100x67px |
| Map Alt: | Highlighted position of Vianen in a municipal map of Utrecht |
| Coordinates: | 52°N 11°W |
| Subdivision Type: | Country |
| Subdivision Name: | Netherlands |
| Subdivision Type1: | Province |
| Subdivision Name1: | Utrecht |
| Subdivision Type2: | Municipality |
| Subdivision Name2: | Vijfheerenlanden |
| Extinct Title: | Merged |
| Extinct Date: | 2019 |
| Unit Pref: | Metric |
| Area Total Km2: | 42.39 |
| Area Land Km2: | 39.45 |
| Area Water Km2: | 2.94 |
| Population Note: | Source: CBS, Statline. |
| Population Total: | 20423 |
| Population As Of: | November, 2018 |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postcode |
| Postal Code: | 4130–4133 |
| Area Code Type: | Area code |
| Area Code: | 0347 |
Vianen (in Dutch; Flemish pronounced as /viˈjaːnə(n)/) is a city and a former municipality in the central Netherlands, in the province of Utrecht. It is located south of the Lek river. Before 2002 it was part of the province of South Holland. Vianen is made up of a historic town centre that dates back to the medieval period and was once surrounded by a defensive wall (parts of which still stand today) and moat, as well as more extensive modern housing developments to the east, south and southwest and an industrial and commercial area. Vianen is intersected by two major motorways leading to the city of Utrecht: the A2 (Amsterdam-Maastricht) and the A27 (Breda-Almere).The municipality was merged with the municipalities of Leerdam and Zederik on 1 January 2019. The name of the new municipality is Vijfheerenlanden which is part of the Utrecht province.
Vianen received city rights in 1337. Vianen thrived under the counts of Brederode, who acquired its lordship through marriage early in the 15th century. It formed a self-proclaimed sovereign seignory till 1795, including Vianen, Lexmond, Hei- en Boeicop and Meerkerk. During the Middle Ages, as a "free city," Vianen could be a haven for felons and escaped serfs. Of the three castles built during the town's history, Batestein Castle was said to be one of the most beautiful in the Netherlands. Its only remnants are a 17th-century brick gate and water-pump. Remnants of the old city wall are visible girdling parts of the old downtown.
Vianen celebrates its city rights every year in October with a traditional horse market. Besides the horses there are also other activities on this day, such as a fair and market and traditional Dutch games.