Pepinster ( or ) is a municipality of Wallonia located in the province of Liège, Belgium.
On 1 January 2006 Pepinster had a total population of 9,560. The total area is 24.79 km<sup>2</sup> which gives a population density of 386 inhabitants per km<sup>2</sup>. Pepinster is situated at the confluence of the rivers Hoëgne and Vesdre.
The municipality consists of the following districts: , Pepinster (including the hamlet of Tancrémont), Soiron, and .
Pepinster was hit extremely hard by the 2021 European floods, the village was temporarily cut off from roads.