SID Factory II is a cross-platform music editor for editing SID music that can be played on a Commodore 64. It uses the reSID emulator. The project was started by Thomas Egeskov Petersen (also known as Laxity) with assistance by Jens-Christian Huus and Michel de Bree.

The editor has been compiled for Windows and Mac under GNU General Public License v2.

You can download the editor here.