The Aïgue Longue (French pronunciation: [aiɡ lɔ̃ɡ]; or Aygue Longue) is a left tributary of the Luy de Béarn, at Mazerolles, Pyrénées-Atlantiques, in the Southwest of France.

[1] Its name means 'long water (stream)'.

The Aïgue Longue rises in the moor of Pont-Long in the north of Pau.

It flows through the lake of Uzein and joins the Luy de Béarn, 77 kilometres (48 mi) upstream from Mazerolles, Pyrénées-Atlantiques, in a parallel motion with the Uzan.

A dam near Mazerolles forms a reservoir named Lac de L'Aigue Longue.