One of the most important features of wxWidgets is cross-platform portability; it currently supports Windows, macOS X, Linux (with the X11, Motif, and GTK+ libraries), OS/2, and several other operating systems and platforms (including an embedded version that is currently under development).
wxWidgets can best be described as a native mode toolkit because it provides a thin API abstraction layer across platforms and uses platform-native widgets under the hood, as opposed to emulating them. Using native controls gives wxWidgets applications a natural and familiar look and feel. On the other hand, introducing an additional layer can result in a slight performance penalty, although this is unlikely to be noticed in the kind of applications we will commonly develop.
wxWidgets is not restricted to GUI development. It's more than just a graphics toolkit, providing a whole set of additional facilities, such as database libraries, an inter-process communication...