Ober Kostenz is a municipality located in the state of Rhineland-Palatinate, Germany. It is situated within the Rhein-Hunsrück-Kreis district and functions as an Ortsgemeinde, which is a type of local municipality belonging to a collective municipality.
The village belongs to the Verbandsgemeinde of Kirchberg. The administrative seat for this collective municipality is located in the town of Kirchberg.