Arrast-Larrebieu (French pronunciation: [aʁast laʁbjø]; Occitan: Tralhar; Basque: Ürrustoi-Larrebille) is a commune in the Pyrénées-Atlantiques department in the Nouvelle-Aquitaine region of south-western France.

Arrast-Larrebieu is located in the former province of Soule some 12 km east by south-east of Saint-Palais and 10 km north by north-east of Mauléon-Licharre. Access to the commune is by the D243 road which branches off the D11 west of the commune and north of Espès-Undurein and passes through the village before continuing north-east to join the D115. The D135 from the D11 in the west to Moncayolle-Larrory-Mendibieu in the south-east passes through the south of the commune and the hamlet of Larrebieu. The commune is mainly farmland with many forests scattered throughout the commune.

The Laxubie rises in the south of the commune and flows north past the village gathering many tributaries and joins the Apaure north of the commune. Several small streams rise in the west of the commune and flow west to join the Saison.

The commune name in basque today is Ürrüstoi-Larrabile or Ürrustoi-Larrebille.

Jean-Baptiste Orpustan indicated that the spelling in Basque Arrast is sometimes given with the determinant Ürrüxtoia meaning "hazel tree grove". He also stated that larrabil means a "rounded moor, squat".

The following table details the origins of the commune name and other names in the commune.

Sources:

Origins: