How do I create child windows with Python tkinter?

You create child windows by creating instances of Toplevel. See http://effbot.org/tkinterbook/toplevel.htm for more information.

Here’s an example that lets you create new windows by clicking on a button:

import Tkinter as tk

class MainWindow(tk.Frame):
    counter = 0
    def __init__(self, *args, **kwargs):
        tk.Frame.__init__(self, *args, **kwargs)
        self.button = tk.Button(self, text="Create new window", 
                                command=self.create_window)
        self.button.pack(side="top")

    def create_window(self):
        self.counter += 1
        t = tk.Toplevel(self)
        t.wm_title("Window #%s" % self.counter)
        l = tk.Label(t, text="This is window #%s" % self.counter)
        l.pack(side="top", fill="both", expand=True, padx=100, pady=100)

if __name__ == "__main__":
    root = tk.Tk()
    main = MainWindow(root)
    main.pack(side="top", fill="both", expand=True)
    root.mainloop()