Change Qt5 Apps Theme to Make Them Look Native in Ubuntu 20.04

Found that Qt5 based applications (e.g., VLC, qBittorrent, Virtualbox, Audacious, etc.) look ugly on Ubuntu Desktop? That’s because they don’t inherit the global GTK theme.

You can apply a custom theme to Qt5 applications to make them look native on Ubuntu Gnome desktop. And Kvantum, an SVG-based theme engine, can do the job.

First let’s see the change before and after applying the changes:

And here’s step by step guide shows how to to this in Ubuntu 18.04, Ubuntu 20.04, Ubuntu 20.10.

1. First open terminal (Ctrl+Alt+T) and run command to add the PPA:

sudo add-apt-repository ppa:papirus/papirus

This step is optional for Ubuntu 20.04 and higher, as the packages are already made into main repositories.

2. Install the qt5-style-kvantum package by running command:

sudo apt install qt5-style-kvantum

3. Add rule to user’s profile, so the theme engine will handle Qt apps for single user.

echo "export QT_STYLE_OVERRIDE=kvantum" >> ~/.profile

For global, you can edit /etc/environment file and add the line export QT_STYLE_OVERRIDE=kvantum as new line in the end.

4. Log out and log back in. Then launch Kvantum Manager from system app menu.
Navigate to “Change/Delete Theme”, then select and apply KvYaru theme.

Now Qt5 apps should look native if you’re running with default Yaru GTK theme.

Uninstall and restore the changes:

To uninstall the PPA, open terminal and run command:

sudo add-apt-repository --remove ppa:papirus/papirus

To remove the theme engine, run command:

sudo apt install qt5-style-kvantum qt5-style-kvantum-themes

And remember to edit ~/.profile to remove the last line.

gedit ~/.profile