Choose your Platform: full shortcut list + printable PDF
macOS Uses Command (⌘) as the primary modifier, plus Option for a few DevTools-adjacent and window actions. Preferences opens with Command+Comma (the standard Mac convention), and tab cycling uses Ctrl+Tab rather than Command+Tab.
Windows Uses Ctrl as the primary modifier, with Alt for page navigation (back/forward) and window cycling. Preferences opens with Alt+P instead of a Ctrl combination, and Quit is Ctrl+Shift+X.
Linux Matches the Windows shortcut set key for key, since Opera documents Windows and Linux together as one table. The one difference worth knowing: the Windows-logo-key shortcuts (like minimizing a window) map to the Super key on most Linux desktop environments.