Bad Grund (Harz) is a town in the district of Osterode, in Lower Saxony, Germany. It is situated in the western Harz, approx. 7 km west of Clausthal-Zellerfeld, and 10 km north of Osterode am Harz.
Bad Grund is also the name of the former Samtgemeinde ("collective municipality") Bad Grund, of which Bad Grund formed part. It was disbanded in March 2013 and replaced by the Einheitsgemeinde Bad Grund.