The Innbach is a river in Upper Austria with a length of approximately 59 km (37 mi). Its source is near Gaspoltshofen at the foot of the Hausruck [bar; cs; de; nl; ro] hills and empties into the Danube at Wilhering. Its drainage basin covers 196 km² (76 sq mi). After Gaspoltshofen, the Innbach passes the towns of Kematen am Innbach, Pichl bei Wels and Bad Schallerbach, at the mouth of the Trattnach [ceb; de; sv]. Near Eferding, it joins with the Aschach and a few kilometers later flows into the Danube downstream of the Ottensheim-Wilhering Power Station  [de; fr; no].

Due to its high volume, many mills were once located along the Innbach.

The Innbach is populated with many species of fish, among them: brown trout, brook trout, bullhead, minnow, grayling, gudgeon, rainbow trout, chub, barbel, roach, rudd, spirlin, perch, nase, dace, bleak, carp, bream, burbot, pike, zander, and catfish.