Aribo (or Arbo; c. 850 – after 909) was margrave (comes terminalis, "frontier count") of the Carolingian March of Pannonia from 871 until his death.
Aribo was originally appointed by the East Frankish king Louis the German to succeed the Wilhelminer brothers William and Engelschalk I, after they died on campaign against the forces of the Great Moravian realm.
A sign of Aribo's strength after this was that he was unable to be unseated by Arnulf when the latter succeeded as King of East Francia in 887.
He last appeared in a 909 deed, when he and Archbishop Pilgrim of Salzburg were vested with Altmünster Abbey by King Louis the Child.
They held the Archbishopric of Salzburg and the office of a Bavarian count palatine in the 10th century, but eventually were pushed out of power in the Duchy of Bavaria by the Liutpoldings.