Mandel lies in the Naheland (the region either side of the River Nahe), south of the Hunsrück, some 5 km west of Bad Kreuznach amidst vineyards, meadows and woodland.
Clockwise from the north, Mandel's neighbours are the municipalities of Sankt Katharinen, Roxheim, Rüdesheim an der Nahe, Weinsheim, Sponheim and Braunweiler, all of which likewise lie within the Bad Kreuznach district.