GUI Toolkit

A GUI Toolkit provides facilities for creating and maintaining GUI's. Tk, which was created expressly for Tcl by John Ousterhout, is the predominant GUI toolkit for Tcl.

GUI Toolkits

going strong for over two decades, and still considered by many to be the most productive tool for GUI development
Fox Toolkit
cross-platform, licensed under the LGPL, written in C++, focused on using a low-level interface on supported platforms, no Tcl bindings yet
cross-platform, dual-licensed, written in C++
cross-platform, license similar to but more permissive than LGPL, written in C++

See Also

Alternative GUI toolkits
could probably be folded into this page