Change OptionMenu based on what is selected in another OptionMenu

Yes, it is possible. With StringVar.trace you can check when the first option has been changed. Then delete all the options of the second OptionMenu and populate it with the corresponding options. If you have a data structure like a dictionary behind this, it can be very easy to map the correspondences:

import sysif sys.version_info[0] >= 3:    import tkinter as tkelse:    import Tkinter as tkclass App(tk.Frame):    def __init__(self, master):        tk.Frame.__init__(self, master)        self.dict = {'Asia': ['Japan', 'China', 'Malaysia'],                     'Europe': ['Germany', 'France', 'Switzerland']}        self.variable_a = tk.StringVar(self)        self.variable_b = tk.StringVar(self)        self.variable_a.trace('w', self.update_options)        self.optionmenu_a = tk.OptionMenu(self, self.variable_a, *self.dict.keys())        self.optionmenu_b = tk.OptionMenu(self, self.variable_b, '')        self.variable_a.set('Asia')        self.optionmenu_a.pack()        self.optionmenu_b.pack()        self.pack()    def update_options(self, *args):        countries = self.dict[self.variable_a.get()]        self.variable_b.set(countries[0])        menu = self.optionmenu_b['menu']        menu.delete(0, 'end')        for country in countries:            menu.add_command(label=country, command=lambda nation=country: self.variable_b.set(nation))if __name__ == "__main__":    root = tk.Tk()    app = App(root)    app.mainloop()

Hi Just to add a little thing. I manage to make 3 dynamic option-menus where two are updated from the previous drop down menu...

from tkinter import *root = Tk()def update_options_B(*args):    countries = data[variable_a.get()]    variable_b.set(countries[0])    menu = optionmenu_b['menu']    menu.delete(0, 'end')    for country in countries:        menu.add_command(label=country, command=lambda nation=country: variable_b.set(nation))def update_options_C(*args):    cities = data2[variable_b.get()]    variable_c.set(cities[0])    menu = optionmenu_c['menu']    menu.delete(0, "end")    for city in cities:        menu.add_command(label=city, command=lambda nation=city: variable_c.set(nation))data = {'Asia': ['Japan', 'China', 'Malasia'],'Europe': ['Germany', 'France', 'Switzerland'], 'Africa': ['Nigeria', 'Kenya', 'Ethiopia']}data2 = {'Japan': ["jiustu", "kamikaz", "Tokyo"], 'China': ["Shaigon", "Hong Kong"], 'Malasia': ["tiramusto", "quala lopour"], 'Germany': ["Dusseldorf", "Berlin", "Hambourg"], 'France': ["Paris", "Lille"], 'Switzerland': ["Biern", "Bonn"], 'Nigeria': ['Nigeria1', 'Nigeria3'], 'Kenya': ["Keny West", "Notorious"], 'Ethiopia': ["Etanpi", "Neeandertaal"]}variable_a = StringVar()variable_b = StringVar()variable_c = StringVar()variable_a.trace('w', update_options_B)variable_b.trace('w', update_options_C)optionmenu_a = OptionMenu(root, variable_a, *data.keys())optionmenu_b = OptionMenu(root, variable_b, '')optionmenu_c = OptionMenu(root, variable_c, '')variable_a.set('Asia')optionmenu_a.pack()optionmenu_b.pack()optionmenu_c.pack()root.mainloop()