Ottmarsfelder Graben is a river of Bavaria, Germany. The river is a three kilometer long brook in the Middle Franconian district of Weißenburg-Gunzenhausen. It flows to the west, and joins the Swabian Rezat at Zollmühle, north of Ellingen. Its upper section, upstream from Ottmarsfeld, is also referred to as the Seiserbach.

• List of rivers of Bavaria