The best replacement for pygtk is pyqt.

The best alternatives to pygtk are rated as following:
★★★★★  pyqt
★★  wxpython
★★  gtk
★★  pygobject
★  tkinter

Your alternative for pygtk is not listed? Suggest!
Speaking about pygtk, one probably shouldn't forget about glade.

Other search terms related to pygtk and their ratings are:
★★★★★ glade
You have in mind a companion for pygtk and it is not yet here? Propose!



Google Trends

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pygtk
pyqt
wxpython