MacTelnet was originally a telnet and FTP client for the Classic Mac OS, and was derived from NCSA Telnet 2.6. It stopped being developed by NCSA at that time, and a new modern version (3.0) was created by Kevin Grant and Ian Anderson.

MacTelnet 4 is a Mac OS X port of MacTelnet 3.0, with major enhancements — including the ability to run any local Unix program, such as a shell, and the ability to connect to more servers (such as SSH servers). This means that MacTelnet, despite its name, is now a complete replacement for Apple's Terminal.