Simon I of Isenburg-Kempenich was the Lord of Isenburg-Kempenich from 1329 until 1341. Simon was a son of Theodoric IV. After his father's death in 1329, he and his brother Theodoric V succeeded him, with his cousin Gerard II who was supported by the Archbishop of Trier. In 1330, Simon made himself the sole ruler of Kempenich, sparking a succession war in which Gerard II brought in his allies, the Counts and Lords of Landskron, Rheineck, Schönberg, Eich, Ölbruck and the Archbishop. Simon and Theodoric also brought in their allies, and formed the "White Sleeves" against Gerard's "Red Sleeves".