Yvoir (French pronunciation: [i.vwaʁ]; Walloon: Uwar) is a municipality of Wallonia located in the province of Namur, Belgium.

The total area is 56.84 km2, making it a population density of 149 inhabitants per km2.

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.