AutoLISP is a dialect of Lisp programming language built specifically for use with the full version of AutoCAD and its derivatives,

which include AutoCAD Map 3D, AutoCAD Architecture and AutoCAD Mechanical. Neither the application programming interface nor the interpreter to execute AutoLISP code are included in the AutoCAD LT product line.

AutoLISP is a small, dynamically scoped LISP (list processing language). It lacks modern LISP features such as a macro system, settable list structure or let bindings. Aside from the core language, most of the primitive functions are for geometry or the manipulation of graphical entities in AutoCAD. The properties of these graphical entities are revealed to AutoLISP as association lists in which AutoCAD “group codes” are paired with values that indicate properties such as points, radii, colors, layers, linetypes, etc. AutoCAD loads AutoLISP code from .LSP files.

AutoLISP code can interact with the user through primitive functions that allow the user to input points, selection sets, numbers and other data. AutoLisp also has a built in GUI mini-language, the Dialog Control Language, for creating interactive forms within AutoCAD.