How to style a Tkinter interface, and how to switch to CustomTkinter

thijs · September 2, 2026, 12:17am

Based on contributions by Erik_Endlich, Daan1.

A default Tkinter interface looks dated out of the box. This guide shows how to style plain Tkinter widgets with colors, fonts, and the ttk module, and how to get a modern look with much less effort using the CustomTkinter library. Read How to create a graphical interface in Python with Tkinter first if you haven’t built a basic Tkinter window yet.

What you need

Python 3 with Tkinter (included in the standard library; on Linux install it with sudo apt install python3-tk if missing).
For the CustomTkinter section: pip install customtkinter and, if you want to display images, pip install pillow.
Patience — styling a GUI is iterative; expect to tweak colors and layout a few times.

Part 1: styling plain Tkinter

1. Set the background and text color

Use bg/background and fg/foreground to set a widget’s colors.

import tkinter as tk

root = tk.Tk()

button = tk.Button(root, text="Click Me", bg="blue", fg="white")
button.pack(pady=20)

root.mainloop()

2. Set a custom font

import tkinter as tk

root = tk.Tk()

label = tk.Label(root, text="Hello, Tkinter!", font=("Helvetica", 16, "bold"))
label.pack(pady=20)

root.mainloop()

3. Add padding and borders

padx/pady add space around a widget; relief and borderwidth control its border style.

import tkinter as tk

root = tk.Tk()

button = tk.Button(root, text="Click Me", relief="raised", borderwidth=5)
button.pack(pady=20)

root.mainloop()

4. Switch to `ttk` for modern-looking widgets

The ttk (themed Tkinter) module gives you better-looking, themeable widgets out of the box.

import tkinter as tk
from tkinter import ttk

root = tk.Tk()

button = ttk.Button(root, text="Styled Button")
button.pack(pady=20)

root.mainloop()

5. Apply a built-in theme

ttk ships with a few built-in themes: "clam", "alt", "classic", "default", and more depending on your platform.

import tkinter as tk
from tkinter import ttk

root = tk.Tk()

style = ttk.Style()
style.theme_use("clam")

button = ttk.Button(root, text="Styled Button")
button.pack(pady=20)

root.mainloop()

6. Customize a widget style with `ttk.Style`

For full control, define a named style and apply it to specific widgets. style.configure("TButton", ...) affects all ttk.Button widgets that use that style.

import tkinter as tk
from tkinter import ttk

root = tk.Tk()

style = ttk.Style()
style.configure("TButton", font=("Verdana", 12), background="green", foreground="white")

button = ttk.Button(root, text="Styled Button", style="TButton")
button.pack(pady=20)

root.mainloop()

7. Put it together: a styled control panel

This combines a grid() layout, a custom ttk theme, two named button styles (green for normal actions, red for Stop), and hover colors via style.map(...).

import tkinter as tk
from tkinter import ttk


class Application:
    def __init__(self, root):
        self.root = root
        self.root.title("Modern Tkinter Buttons")

        self.top_frame = tk.Frame(self.root)
        self.top_frame.grid(row=0, column=0, padx=20, pady=20)

        self.style = ttk.Style()
        self.style.theme_use("alt")  # a more modern base theme

        # style for normal action buttons
        self.style.configure(
            "TButton",
            padding=6,
            relief="raised",
            background="#4CAF50",  # green
            foreground="white",
            font=("Arial", 12, "bold"),
        )
        self.style.map("TButton", background=[("active", "#45a049")])  # hover color

        # separate style for the Stop button
        self.style.configure(
            "RedButton.TButton",
            padding=6,
            relief="raised",
            background="#FF5733",  # red
            foreground="white",
            font=("Arial", 12, "bold"),
        )
        self.style.map("RedButton.TButton", background=[("active", "#FF2A00")])

        # make columns/rows scale evenly
        for col in range(4):
            self.top_frame.grid_columnconfigure(col, weight=1)
        for row in range(3):
            self.top_frame.grid_rowconfigure(row, weight=1)

        self.connect_button = ttk.Button(self.top_frame, text="Connect", command=self.connect)
        self.connect_button.grid(row=0, column=0, columnspan=2, padx=5, pady=5, sticky="ew")

        self.disconnect_button = ttk.Button(self.top_frame, text="Disconnect", command=self.disconnect)
        self.disconnect_button.grid(row=0, column=2, columnspan=2, padx=5, pady=5, sticky="ew")

        self.start_button = ttk.Button(self.top_frame, text="Start", command=self.start_process, state="disabled")
        self.start_button.grid(row=1, column=0, columnspan=2, padx=5, pady=5, sticky="ew")

        self.pause_button = ttk.Button(self.top_frame, text="Pause", command=self.pause_process, state="disabled")
        self.pause_button.grid(row=1, column=2, columnspan=2, padx=5, pady=5, sticky="ew")

        self.stop_button = ttk.Button(
            self.top_frame, text="Stop", command=self.stop_process, state="disabled", style="RedButton.TButton"
        )
        self.stop_button.grid(row=2, column=0, columnspan=4, padx=5, pady=5, sticky="ew")

    def connect(self):
        print("Connected")
        self.start_button.config(state="normal")
        self.pause_button.config(state="normal")
        self.stop_button.config(state="normal")

    def disconnect(self):
        print("Disconnected")
        self.start_button.config(state="disabled")
        self.pause_button.config(state="disabled")
        self.stop_button.config(state="disabled")

    def start_process(self):
        print("Process Started")

    def pause_process(self):
        print("Process Paused")

    def stop_process(self):
        print("Process Stopped")


root = tk.Tk()
app = Application(root)
root.mainloop()

Running this gives an interface with Connect/Disconnect buttons and Start/Pause/Stop buttons (Stop styled in red), like this:

Quick reference: common styling options

Option	Description	Example
`bg` / `background`	Background color of the widget	`bg="blue"`
`fg` / `foreground`	Text color	`fg="white"`
`font`	Font type, size, and style	`font=("Arial", 12, "bold")`
`padx`, `pady`	Horizontal/vertical padding	`padx=20, pady=10`
`borderwidth`	Border width	`borderwidth=5`
`relief`	Border style (`flat`, `raised`, …)	`relief="raised"`
`style`	Named `ttk` style to apply	`style="TButton"`
`theme_use()`	Active `ttk` theme	`style.theme_use("clam")`

Part 2: CustomTkinter for a modern look with less effort

CustomTkinter is a drop-in-style alternative to plain Tkinter that looks modern by default, without manually theming every widget. The API is close enough to Tkinter that the concepts from Part 1 (layout, styling widgets) still apply.

1. Install and import

pip install customtkinter

import customtkinter

2. Create the window

root = customtkinter.CTk()

3. Set the appearance mode and color theme

customtkinter.set_appearance_mode("dark")  # or "light"
customtkinter.set_default_color_theme("green")  # or "blue", "dark-blue"

4. Set the window size

Use a fixed size with geometry(), or make it fill the screen:

root.geometry("1920x1080")
# or, to go fullscreen:
# root.attributes("-fullscreen", True)

5. Lay out the interface

Start with a frame to hold your widgets, rather than placing everything directly into root — this keeps larger interfaces organized.

frame1 = customtkinter.CTkFrame(master=root)

You can place widgets with pack() for small interfaces, but for anything non-trivial, use grid(): it gives you rows and columns whose relative sizes you control with weights, so the layout scales cleanly to different screen resolutions (unlike fixed pixel width/height, which does not adapt).

root.grid_rowconfigure(0, weight=1)
root.grid_columnconfigure(0, weight=1)
root.grid_columnconfigure(1, weight=1)
root.grid_columnconfigure(2, weight=2)
root.grid_columnconfigure(3, weight=1)

frame1.grid(row=0, column=2)

Frames can themselves contain a grid of their own widgets, the same way.

6. Add a button

def button_function():
    print("Hoisting mode activated")


hoist_button = customtkinter.CTkButton(
    master=frame1,
    corner_radius=0,
    text="Hoisting mode",
    font=("Arial", 14),
    fg_color="#2b2b2b",
    command=button_function,
)
hoist_button.grid(row=0, column=0, pady=(20, 0), padx=0)

command=button_function connects the button to the function that runs its logic — put your own actions inside button_function.

7. Add an image

from PIL import Image

light_image = Image.open("your_image.jpg")
my_image = customtkinter.CTkImage(light_image=light_image, size=(200, 200))

image_label = customtkinter.CTkLabel(frame1, image=my_image, text="")
image_label.image = my_image  # keep a reference so the image isn't garbage-collected
image_label.grid(row=0, column=0, padx=(20, 0), sticky="")

Troubleshooting

ImportError / “image not found” errors after installing Pillow. Restarting the terminal (or IDE) after installing pillow resolves this in most cases — the interpreter needs to pick up the newly installed package.
Image disappears right after being displayed. This happens when the CTkImage/PhotoImage object gets garbage-collected because nothing keeps a reference to it. Keep a reference on the widget itself, as in image_label.image = my_image above.
Inconsistent variable names for the same frame (e.g. Frame1 in one place and frame1 in another) will raise a NameError. Pick one name and use it consistently.

How to style a Tkinter interface, and how to switch to CustomTkinter

What you need

Part 1: styling plain Tkinter

1. Set the background and text color

2. Set a custom font

3. Add padding and borders

4. Switch to `ttk` for modern-looking widgets

5. Apply a built-in theme

6. Customize a widget style with `ttk.Style`

7. Put it together: a styled control panel

Quick reference: common styling options

Further reading

Part 2: CustomTkinter for a modern look with less effort

1. Install and import

2. Create the window

3. Set the appearance mode and color theme

4. Set the window size

5. Lay out the interface

6. Add a button

7. Add an image

Troubleshooting

Related

How to style a Tkinter interface, and how to switch to CustomTkinter

What you need

Part 1: styling plain Tkinter

1. Set the background and text color

2. Set a custom font

3. Add padding and borders

4. Switch to ttk for modern-looking widgets

5. Apply a built-in theme

6. Customize a widget style with ttk.Style

7. Put it together: a styled control panel

Quick reference: common styling options

Further reading

Part 2: CustomTkinter for a modern look with less effort

1. Install and import

2. Create the window

3. Set the appearance mode and color theme

4. Set the window size

5. Lay out the interface

6. Add a button

7. Add an image

Troubleshooting

Related

4. Switch to `ttk` for modern-looking widgets

6. Customize a widget style with `ttk.Style`