Is there a way to make a Tkinter GUI window that the user can not change the size of?

This should do it ...

# make a Tkinter window that is not resizable
# also disables the maximize button

from Tkinter import *

root = Tk()
# root.resizable(0, 0) or in detail ...
root.resizable(width=FALSE, height=FALSE)

# your code here .....

root.mainloop()

Ah, that seems to work for me, thanks!