The Friedberger Ach is a river in Bavaria, Germany.

Its source is in the village Untermühlhausen, northeast of Landsberg am Lech.

For most of its length it flows parallel to the river Lech at only a few km distance.

Towns along the Friedberger Ach include Weil, Prittriching, Mering, Friedberg, Rehling, Thierhaupten and Rain.

This article related to a river in Bavaria is a stub.