Theodoric I of Isenburg-Kempenich (German: Dietrich I von Isenburg-Kempenich) was a Lord of Isenburg-Kempenich co-ruling with his brother Florentin. Theodoric I was a son of Reynold, whom he and Florentin succeeded sometime before 1158. Theodoric and Florentin were mentioned in a document of the Holy Roman Emperor Frederick I Barbarossa in 1158, and in another document in 1166 where Countess Hildegund of Are donated an abbey to the Archbishopric of Cologne. Theodoric and Florentin were also witnesses in 1173 to the granting of independence to the Abbey of Siegburg. Theodoric had died sometime before 1186. His sons, Salentin, Rosemann and Theodoric II eventually succeeded his brother Florentin.