Support varies by desktop environment

Unlike Windows and macOS, Linux emoji support depends heavily on which desktop environment you're running — GNOME, KDE Plasma, and others each handle it differently, and some minimal window managers don't include a picker at all.

GNOME

Many GNOME-based distributions, including recent Ubuntu releases, support Ctrl + . to open an emoji picker, though the exact shortcut can vary by version.

KDE Plasma

KDE Plasma includes its own character/emoji selector, usually accessible through a keyboard shortcut configurable in system settings rather than a fixed default across all versions.

A dependable cross-distro option

Because Linux emoji support is inconsistent across distributions and desktop environments, a browser-based emoji keyboard is often the most reliable option regardless of which distro or window manager you're running.