How do I close a tkinter window?

def quit()
    root.quit()

or

def quit()
    root.destroy()

import tkinter as tk

def quit(root):
    root.destroy()

root = tk.Tk()
tk.Button(root, text="Quit", command=lambda root=root:quit(root)).pack()
root.mainloop()

The usual method to exit a Python program:

sys.exit()

(to which you can also pass an exit status) or

raise SystemExit

will work fine in a Tkinter program.

In case anyone wants to bind their Escape button to closing the entire GUI:

master = Tk()
master.title("Python")

def close(event):
    sys.exit()

master.bind('<Escape>',close)
master.mainloop()

The easiest way would be to click the red button (leftmost on macOS and rightmost on Windows). If you want to bind a specific function to a button widget, you can do this:

class App:
    def __init__(self, master)
        frame = Tkinter.Frame(master)
        frame.pack()
        self.quit_button = Tkinter.Button(frame, text = 'Quit', command = frame.quit)
        self.quit_button.pack()

Or, to make things a little more complex, use protocol handlers and the destroy() method.

import tkMessageBox

def confirmExit():
    if tkMessageBox.askokcancel('Quit', 'Are you sure you want to exit?'):
        root.destroy()
root = Tk()
root.protocol('WM_DELETE_WINDOW', confirmExit)
root.mainloop()

you only need to type this:

root.destroy()

and you don't even need the quit() function cause when you set that as commmand it will quit the entire program.

you dont have to open up a function to close you window, unless you're doing something more complicated:

from Tkinter import *

root = Tk()
Button(root, text="Quit", command=root.destroy).pack()
root.mainloop()

I normally use the default tkinter quit function, but you can do your own, like this:

from tkinter import *
from tkinter.ttk import *

window = Tk()
window.geometry('700x700') # 700p x 700p screen

def quit(self):
    proceed = messagebox.askyesno('Quit', 'Quit?')
    proceed = bool(proceed) # So it is a bool

    if proceed:
        window.quit()
    else:
        # You don't really need to do this
        pass

btn1 = Button(window, text='Quit', command=lambda: quit(None))

window.mainloop()

For menu bars:

def quit():
    root.destroy()

menubar = Menu(root)
filemenu = Menu(menubar, tearoff=0)

filemenu.add_separator()

filemenu.add_command(label="Exit", command=quit)
menubar.add_cascade(label="menubarname", menu=filemenu)
root.config(menu=menubar)
root.mainloop()

I use below codes for the exit of Tkinter window:

from tkinter import*
root=Tk()
root.bind("<Escape>",lambda q:root.destroy())
root.mainloop()

or

from tkinter import*
root=Tk()
Button(root,text="exit",command=root.destroy).pack()
root.mainloop()

or

from tkinter import*
root=Tk()
Button(root,text="quit",command=quit).pack()
root.mainloop()

or

from tkinter import*
root=Tk()
Button(root,text="exit",command=exit).pack()
root.mainloop()

Code snippet below. I'm providing a small scenario.

import tkinter as tk
from tkinter import *

root = Tk()

def exit():
    if askokcancel("Quit", "Do you really want to quit?"):
        root.destroy()

menubar = Menu(root, background='#000099', foreground='white',
               activebackground='#004c99', activeforeground='white')

fileMenu = Menu(menubar,  tearoff=0, background="grey", foreground='black',
                activebackground='#004c99', activeforeground='white')
menubar.add_cascade(label='File', menu=fileMenu)

fileMenu.add_command(label='Exit', command=exit)

root.config(bg='#2A2C2B',menu=menubar)

if __name__ == '__main__':
    root.mainloop()

I have created a blank window here & add file menu option on the same window(root window), where I only add one option exit.

Then simply run mainloop for root.

Try to do it once

Of course you can assign the command to the button as follows, however, if you are making a UI, it is recommended to assign the same command to the "X" button:

def quit(self): # Your exit routine
   self.root.destroy()

self.root.protocol("WM_DELETE_WINDOW", self.quit) # Sets the command for the "X" button 

Button(text="Quit", command=self.quit) # No ()

There is a simple one-line answer:

Write - exit() in the command

That's it!