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".

Both sides plundered and terrified the population in and around Kempenich. In 1331 Simon took the church of Kempenich to use its ecclesiastical office against the Red Sleeves. Gerard of Landskron burnt the church down, however, and both Simon and Gerard were excommunicated by Archbishop Baldwin of Luxembourg. On 11 June 1331 the Peace of Lahnstein was signed in which Simon was confirmed as the sole ruler of Kempenich and his excommunication was lifted. Simon died in 1341 and was succeeded by his son Simon II; Gerard died without any children prior.

Preceded by:

Simon I

Succeeded by:

Theodoric IV Lord of Isenburg-Kempenich
1329 - 1341
with... Theodoric V and Gerard II
1329 - 1330
Simon II