GAP is a free software system for doing computational discrete algebra, written by the mathematics department at the Crest School of Mathematics and Statistics, St. Andrews, Scotland.

GAP is similar to software like Mathematica and Matlab in that it allows symbolic computation, but while the latter also provide many numerical capabilities and include powerful visualization tools, GAP purely focuses on the needs of discrete mathematicians and is stocked with features and concepts from the highly theoretical and purely discrete world of group theory and higher algebra.