tkinter_in_thread.py

# -*- coding: utf-8 -*-

import tkinter as tk
import threading

class App(threading.Thread):

    def __init__(self):
        threading.Thread.__init__(self)
        self.start()

    def requestQuit(self):
        self.root.quit()

    def run(self):
        self.root = tk.Tk()
        self.root.protocol("WM_DELETE_WINDOW", self.requestQuit)

        label = tk.Label(self.root, text="Hello World")
        label.pack()

        self.root.mainloop()


app = App()
print('Now we can continue running code while mainloop runs!')

for i in range(100):
    print(i)