The Widonids () were an Italian family of Frankish origin prominent in the 9th century.
They were an aggressive dynasty that expanded their power base, the Duchy of Spoleto, at the expense of the neighboring Papal States and in alliance with the Carolingian dynasty, to whom they were related through the female line and thus were able to aspire to the imperial throne. The Widonids and the Rorgonids competed for control of the Breton March through much of the ninth century.
The first member of the family to attain prominence was Lambert's son Guy I, who was made duke of Spoleto by the Emperor Lothair I in 842. He was active in Lotharingia and Italy, even marrying a local Lombard woman, Itta (or Itana), the daughter of Sico of Benevento. His descendants continued to rule Spoleto until 897.
The most famous Guidoni were Guy III and his son Lambert II. Both became kings of Italy and emperors. Guy IV of Spoleto also became Duke of Benevento.