Theodoric I (German: Theoderich, also Theodor or Dietrich) (died 916) was the Bishop of Paderborn from 908 to 916. Virtually no record of Theodoric's life and work has survived. However, it was the period of the Hungarian invasions of Europe and the conflicts between the Saxon and Frankish duchies. During the revolt by Duke Henry the Fowler against King Conrad the Saxon bishops aligned themselves with Henry. At the hill castle of Eresburg (Marsberg) in the Bishopric of Paderborn a bloody feud arose in 915 in which Theoderic was also supposed to have participated militarily.