There are a few other choices for multi-platform GUI programming. Just not too many, and the ones other than wxWidgets and Qt are not so well known a.k.a. menti

There are a few other choices for multi-platform GUI programming. Just not too many, and the ones other than wxWidgets and Qt are not so well known a.k.a. mentioned so often on the net. But they exist. There's a Wikipedia page with a list of GUI toolkits. I've tried a few of them briefly, earlier. FLTK (Fast Light Tool Kit) and Fox toolkit are two. Some of them are in C/C++ but some of those have bindings for Python, Ruby, etc. IUP is another that seems interesting, saw it recently. Has bindings only for C and Lua, IIRC. It's from the same Brazilian institute where Lua was created. Also, the reason not too many have become mainstream (like wx and Qt) is probably largely because it's quite a difficult job to create a new one, even on one OS only [1], unless all you are doing is thinly wrapping an existing native toolkit. I read some about this in a book that goes somewhat into the internals of Qt3 or 4. [1] and cross-platform is harder still.