Yvoir (; ) is a municipality of Wallonia located in the province of Namur, Belgium.
On 1 January 2006 the municipality had 8,450 inhabitants. The total area is 56.84 km<sup>2</sup>, making it a population density of 148.66 inhabitants per km<sup>2</sup>.
The municipality consists of the following districts: Dorinne, Durnal, Evrehailles, Godinne, Houx, Mont, Purnode, Spontin and Yvoir.
Yvoir was the host city of the 1975 UCI Road World Championships.
Yvoir hosts the Mont-Godinne site of the CHU UCLouvain Namur university hospital, serving as teaching hospital for the University of Louvain.