Mittelberg is a municipality and a village in the district of Bregenz in the Kleinwalsertal, in the Austrian state of Vorarlberg. It is accessible by road only from Germany.

The largest stream in the municipality is the Breitach which originates in Baad and flows through all three villages of Mittelberg, Hirschegg and Riezlern. It receives water of the side streams such as Derrabach, Turabach, Bärgundbach, Gemstelbach and Wildenbach.

The main mountains of Mittelberg include Elfer (2387 m) Bärenkopf (Allgäu Alps) (2083 m), Walmendingerhorn (1990 m), Grosser Widderstein (2536 m) and Zwölfer (2224 m).

Kleinwalsertal is a valley that is accessible by road only from Germany.