Haselbach is a municipality in the district of Straubing-Bogen, in the German state of Bavaria. It is one of the smaller communities within that district, which lies in the eastern part of Bavaria.
As a municipality, Haselbach forms part of the local administrative structure of the Straubing-Bogen district, a district centred on the city of Straubing. The surrounding region is part of Bavaria's Lower Bavaria administrative area.