List of alternative shells for Windows

This is a list of software that provides an alternative graphical user interface for Microsoft Windows operating systems. The technical term for this interface is a shell. Windows' standard user interface is the Windows shell; Windows 3.0 and Windows 3.1x have a different shell, called Program Manager. The programs in this list do not restyle the Windows shell, but replace it; therefore, they look and function differently, and have different configuration options.