French: Galoppe) is a 21 kilometres (13 mi) long river in eastern Belgium and southeastern Netherlands.

During Roman times, the river was called Galopia or Gulippa, meaning little Geul or upper brook.

[disputed – discuss] The Gulp is a real trout stream: flowing fast and rich in oxygen.

From its source in Henri-Chapelle, a village of the municipality of Welkenraedt, province of Liège it runs in a northwestern direction across the Dutch border, after which it flows into the Geul.

This happens near a motte-and-bailey castle called "Burggraaf" at Gulpen, where also the Eyserbeek river joins the Geul from the opposite bank.