SNNS (Stuttgart Neural Network Simulator) is a neural network simulator originally developed at the University of Stuttgart.

While it was originally built for X11 under Unix, there are Windows ports[citation needed].

SNNS is written around a simulation kernel to which user written activation functions, learning procedures and output functions can be added.

It has support for arbitrary network topologies and the standard release contains support for a number of standard neural network architectures and training algorithms.

In July 2008 the license was changed to the GNU LGPL.