wxGlade has been tested and run on Windows, Linux, Mac OSX.
Because wxGlade is written in Python using wxPython, it can also be run on any platform that supports Python and wxPython.
Especially the wxGlade requirements are:
Python 2 - at least 2.3 or any later version of Python 2
wxPython 2.6, 2.8 or 30
wxWidgets 2.6, 2.8 or 3.0, the wxWidgets are often bundled with wxPython
The support for wxWidgets 3.0 as well as wxPython 3.0 based currently on the development release series 2.9 of wxPython.
wxWidgets is available at http://www.wxwidgets.org and wxPython at http://www.wxpython.org.