Tkinter provides only a small number of basic widgets, and lacks a collection of more modern widgets. It needs ttk, Pmw, Tix, and other extensions to provide some really useful widgets. Even with these extensions, Tkinter fails to match the range of widgets provided by other GUI tools, such as wxPython advanced widget set and PyQt.

For instance, wxPython's HtmlWindow widget lets the user display HTML content with ease. There have been attempts to provide similar extensions in Tkinter, but they are far from satisfactory. Similarly, there are other widgets from Advanced User Interface Library and mixins in wxPython, such as floating/docking frames, perspective loading and saving, and others, which Tkinter users can only hope to be included in future releases.

Tkinter supporters often tend to refute this criticism by citing how easily you can construct new widgets from a collection of basic widgets.

Tkinter is rightfully criticized for providing no support for printing features. Compare this to wxPython, which provides a complete printing solution in the form of a printing framework.

Tkinter natively does not support image formats such as JPEG and PNG. The PhotoImage class of Tkinter can read images only in GIF and PGM/PPM formats.

Although there are workarounds, such as using ImageTk and Image submodules from the PIL module, it would have been better if Tkinter natively supported the popular image formats.

Tkinter is often criticized as having a relatively inactive development community. This is true to a large extent. The documentation of Tkinter has remained a work-in-progress for many years now.

A large number of Tkinter extensions appeared over the years, but most of them have not been under active development for a long time.

Tkinter supporters refute this with the logic that Tkinter is a stable and mature technology that does not need frequent revisions like some other GUI modules that are being newly developed.