Stephan I, Count of Sponheim (d. ca. 1080) is the patriarch of the Rhenish branch of the House of Sponheim, which ruled over the County of Sponheim. He was closely related to Siegfried I, Count of Sponheim, patriarch of the Carinthian Sponheimish branch, but the exact relationship between the two dynasts is disputed. Johannes Trithemius credits a Count Eberhard of Sponheim as founder of the Abbey of Sponheim and dates the founding to 1044, position questioned by Johannes Mötsch. The Genealogia Sponhemica presents Count Eberhardus as son of Countess Hedwig and father of a single Count Stephanus I/II of Sponheim (). Donald C. Jackman considers Stephan I a son of Siegfried I. Both Jackman and Josef Heinzelmann consider Stephan as being identical to Stephan, Vogt of Worms documented with his b