Extensions are specially written library (.DLL) files that add new commands, functions and dialog elements to DialogScript. The BROWSER and IMAGE dialog elements and associated commands and functions are implemented using extensions.

To use an extension in a DialogScript program, it must first be loaded using the EXTERNAL command. The commands and functions that it adds must also be declared to the compiler using the #DEFINE directive. Some extensions may include a unit containing the necessary definitions, which may be included in your program using a #INCLUDE directive.

Extensions may be created using programming languages such as C or Delphi, but not in DialogScript. Extensions may be purchased from Commercial Research and other software developers.