Ottignies-Louvain-la-Neuve (French pronunciation: [ɔtiɲi luvɛ̃ la nœv] ⓘ; Walloon: Ocgniye-Li Noû Lovén) is a city and municipality of Wallonia located in the Belgian province of Walloon Brabant.

The municipality consists of the following sub-municipalities: Ottignies, Louvain-la-Neuve, Céroux-Mousty, and Limelette.

Louvain-la-Neuve (sometimes abbreviated as "LLN") is a new town developed from 1968 in order to provide a home for the University of Louvain (UCLouvain), the French-speaking part of the former Catholic University of Louvain on its separation from the Dutch-speaking part, which remained in the ancient city of Louvain (Leuven).

It covers 231 hectares (570 acres) spread over the area of the town of Ottignies-Louvain-la-Neuve and the municipality of Mont-Saint-Guibert (30 kilometres (19 mi) away from Brussels).

The Lhoist group, world leader in the lime, dolime and mineral solutions, has its head office in Ottignies-Louvain-la-Neuve (Limelette).