Lierneux (French pronunciation: [ljɛʁnø]; Walloon: Lierneu) is a municipality of Wallonia located in the province of Liège, Belgium.

On January 1, 2006, Lierneux had a total population of 3,367. The total area is 92.08 km which gives a population density of 37 inhabitants per km. Lierneux is known for its psychiatric hospital CHS l'Accueil.

The municipality consists of the following districts: Arbrefontaine, and Bra, and Lierneux.

Within the bounds of the municipality a lies a memorial site to the tribute of the 82nd Airborne Division who won the Battle of the Bulge against the German SS division December 22, 1944.

• List of protected heritage sites in Lierneux

• Hendriks, Jan (1995). A Hell in the Snow the Battle Near Grand Sart (Lierneux) on January 7th 1945. Birds Nest Books (Missoula, MT, U.S.A.).

• Media related to Lierneux at Wikimedia Commons