LXQt on Ubuntu 24.04: Lightweight Desktop Setup Guide

If GNOME feels sluggish on your hardware and even Xfce seems heavier than it should, LXQt is the desktop worth trying — a Qt-based environment that idles around 350 MB of RAM while still delivering a proper desktop with a file manager, panel, session management, and sane defaults. On Ubuntu 24.04, LXQt 1.4 ships in the repositories (and Lubuntu 24.04 uses it as the default), making installation trivial. This guide walks through setting up LXQt on a stock Ubuntu system, configuring it for daily productivity, and squeezing every bit of performance out of older machines. Having deployed LXQt on everything from repurposed Core 2 Duo laptops to Raspberry Pi 4 units, we can say with confidence that it punches well above its weight.

Installing LXQt on Ubuntu 24.04

From a stock Ubuntu or any flavour:

sudo apt install lxqt

This pulls in the core desktop: the LXQt panel, PCManFM-Qt file manager, QTerminal, LXQt Session, the Openbox window manager, and the LXQt configuration centre. To add a broader set of default applications:

sudo apt install lubuntu-desktop

The lubuntu-desktop metapackage includes additional applications tuned for the Lubuntu experience: FeatherPad (text editor), LXImage-Qt (image viewer), Screengrab (screenshots), and the Discover software centre.

Log out, select “LXQt Desktop” from the session menu on the login screen, and log in.

First Boot Configuration

Panel Layout

LXQt ships with a single bottom panel that includes an application menu, task manager, system tray, clock, and desktop switcher. This is functional but minimal. Consider these adjustments:

Add a Quick Launch bar: Right-click the panel → Manage Widgets → Add Widget → Quick Launch. Drag your most-used applications (terminal, file manager, browser) into it.

Move the panel to the top (if you prefer): Right-click the panel → Configure Panel → Position → Top of Desktop. This frees the bottom of the screen for application windows and feels more natural if you are coming from GNOME or macOS.

Theme and Appearance

LXQt uses Qt for its own components and can use either GTK or Qt themes for applications. For a cohesive look:

1. Open LXQt Configuration Centre → Appearance
2. Set the LXQt theme to “Ambiance” or “Kvantum” for a modern look
3. Install Kvantum for advanced Qt theming:

   sudo apt install qt5-style-kvantum
   

4. Open Kvantum Manager, select a theme (KvArc is excellent), and apply it

For GTK applications (Firefox, GIMP), set the GTK theme through LXQt Configuration Centre → Appearance → GTK Style.

File Manager: PCManFM-Qt

PCManFM-Qt is fast and capable. Enable useful features:

• Dual pane mode: View → Split View (shortcut: F3)
• Show hidden files: View → Show Hidden Files (Ctrl+H)
• Thumbnail previews: Edit → Preferences → Display → check “Show thumbnails of files”

Keyboard Shortcuts

LXQt uses Openbox for window management by default. Configure keyboard shortcuts in ~/.config/openbox/lxqt-rc.xml. Common additions:

<keybind key="W-t">
  <action name="Execute">
    <command>qterminal</command>
  </action>
</keybind>
<keybind key="W-e">
  <action name="Execute">
    <command>pcmanfm-qt</command>
  </action>
</keybind>

After editing, reload Openbox: openbox --reconfigure.

Performance Tuning for Older Hardware

Disable Compositing

Openbox does not include a compositor by default, which is actually an advantage on older GPUs — no compositing means no extra GPU overhead. If you added picom or compton, consider removing it on machines with integrated graphics older than Intel HD 4000.

Reduce Swap Usage

If your machine has limited RAM, configure swappiness to keep more data in memory:

echo 'vm.swappiness=10' | sudo tee -a /etc/sysctl.d/99-swappiness.conf
sudo sysctl -p /etc/sysctl.d/99-swappiness.conf

Use a Lightweight Browser

Firefox and Chrome are RAM-heavy. On machines with 2–4 GB RAM, consider:

• Falkon — a Qt-based browser that integrates well with LXQt
• Midori — minimal WebKit-based browser

sudo apt install falkon

Disable Unnecessary Services

Check what is running at startup:

systemctl list-unit-files --state=enabled

On a minimal machine, you can safely disable services like cups (if no printer), bluetooth (if no Bluetooth hardware), and ModemManager (if no cellular modem):

sudo systemctl disable cups bluetooth ModemManager

LXQt vs Xfce: Honest Comparison

Both target the “lightweight but usable” niche. Here is how they compare in practice:

LXQt wins on raw efficiency. Xfce wins on customisation depth and GTK theme availability. If your machine has 4 GB+ RAM, either works well. Below 4 GB, LXQt’s advantage is tangible.

Using LXQt with Wayland (Experimental)

LXQt 1.4 can run under Wayland using the Labwc compositor. This is experimental on Ubuntu 24.04 but functional:

sudo apt install labwc

Select “LXQt (Labwc)” from the session menu at login. Expect some rough edges — screen sharing, clipboard sync, and some panel plugins may not work perfectly yet. By 26.04, this should be much more polished.

If you’re the kind of person who optimises their desktop down to the last megabyte, you’ll appreciate a course that’s equally thorough about the underlying OS. Mastering Linux – The Comprehensive Guide covers everything from process management to kernel tuning.

Related Reading

• Xfce on Ubuntu 24.04 — the other lightweight contender
• Ubuntu 24.04 Post-Install Checklist — general setup steps that apply to any desktop
• Wayland vs Xorg — understanding the display server transition