In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 246.7 million years ago until 241.464 million years ago.

The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895.

The original type locality is at Großreifling in the Austrian state of Styria.

There is no accepted global reference profile for the base, but one (GSSP or golden spike) was proposed at a flank of the mountain Deșli Caira in the Romanian Dobruja.

Especially in Central Europe the Anisian Stage is sometimes subdivided into four substages: Aegean, Bythinian, Pelsonian and Illyrian.