The Ammer (German: [ˈamɐ]) is a small river in Baden-Württemberg, Germany, a tributary of the Neckar.

Along the southern edge of the Schönbuch, it flows through Herrenberg, Ammerbuch, Unterjesingen and Tübingen, before it discharges into the Neckar at Tübingen-Lustnau after 22.6 kilometres (14.0 mi).

From there the Ammer flows through the valley named after it at the southern edge of the Schönbuch nature park as well as the communities Gültstein and Ammerbuch, uniting in Tübingen with the Goldersbach and flows a little later in the Tübingen district Lustnau from the left into the upper Neckar.

The Aischbach is water-bearing all year round from the time it passes under the embankment of the Stuttgart–Horb railway near Herrenberg station.

Their stream valleys were formed very early in geological history; today, however, these ditches only carry water temporarily after heavy rainfall.