STABL is a computer program written for the general solution of slope-stability problems using a two-dimensional limiting equilibrium method. The original program was developed by Ronald A. Siegel at Purdue University in 1975. STABL was placed on line for routine use in 1976 by the Indiana Department of Highways, and after being reported in the open literature, the program was adopted by many agencies.

The extensive use of STABL for academic purposes originated requests from users to introduce many improvements to the original STABL program since its introduction. Most of the current versions can handle tieback loading, reinforced-earth layers in embankment, and Spencer's method of analysis.STABL programs feature unique, random techniques for generation of potential failure surfaces and the most critical surface is shown in the output as the one with the lowest factor of safety.