Waldo of Reichenau (sometimes Walto) (c. 740 - 814, Paris) was a Carolingian abbot and bishop.
He belonged to a noble Frankish family of the von Wetterau (Conradines). His father was Richbold Count of Breisgau and his older brother was (Rupert) Ruthard Baron von Aargau. In 782 he became Abbot of the Abbey of St. Gall, where he established a library. From 786 until 806 he was Abbot of Reichenau Abbey, where he established a library and a school. Charlemagne made him Bishop of Pavia and Basle in 791. In 805 Charlemagne made him Imperial Abbot and Abbot of the Abbey of St.-Denis in Paris where he died in 814.