| Brixentaler Ache | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Austria |
| Subdivision Type2: | State |
| Subdivision Name2: | Tyrol |
| Subdivision Type3: | Districts |
| Subdivision Name3: | Kufstein and Kitzbühel |
| Length: | 26.4km (16.4miles) |
| Source1 Location: | Einködlscharte on the mountain in Brixen im Thale |
| Mouth Location: | near Wörgl into the Inn |
| Basin Population: | ca. 14,000 |
| Basin Size: | 329km2 |
| Tributaries Left: | Windauer Ache, Kelchsauer Ache |
| Custom Label: | Navigable |
| Custom Data: | not navigable |
The Brixentaler Ache is a river of Tyrol, Austria, a right tributary of the Inn. It passes through the districts of Kitzbühel and Kufstein. It is one of the largest tributaries of the Inn in the Tyrolean Unterland by catchment area, but is only long.
The Brixentaler Ache rises as the Brixenbach in the territory of Brixen im Thale and flows westwards through the Brixental, a southeastern valley of the Lower Inn Valley. Between Westendorf and Hopfgarten im Brixental (the main village in the valley), the valley floor narrows. Immediately after this bottleneck the Windauer Ache joins the Brixenbach from the south. From this confluence the Brixenbach is known as the Brixentaler Ache. After about one kilometre the larger Kelchsauer Ache joins the river (also from the south). The long Kelchsauer Ache drains the entire Kelchsau area.
Between Hopfgarten and the section of river forming the boundary between Kirchbichl and Wörgl, the Ache is again forced through a gorge, before it breaks out into the plains of the Inn Valley. On leaving the gorge the Ache is impounded by a large weir and part of the water is diverted into a channel that leads to a small power station run by Tiroler Wasserkraft. Below the weir the Luecher Bach enters the main stream from the direction of Söll to the north. After having been fed by so much water from its large tributaries the Ache now dominates the landscape of the broad and densely settled Brixental valley. After the now around wide Brixentaler Ache has flowed through Wörgl, it discharges from the south into the Inn.
The river's catchment area is relatively large, especially as a result of its tributaries, the Windauer Ache and Kelchsauer Ache, and covers about a third of the territory of Kitzbühel District.