Shortcuts for tabs:
Ctrl + Alt + PageDown Switches to the next tab to the left.
Ctrl + Alt + PageDown Switches to the next tab to the right.
Ctrl + W Close tab.
Ctrl + Shift + L Save all tabs.
Ctrl + Shift + W Close all tabs.
Alt + n Jump to nth tab.

Shortcuts for working with files:
Ctrl + N Create a new document.
Ctrl + O Open a document.
Ctrl + L Open a location.
Ctrl + S Save the current document to disk.
Ctrl + Shift + S Save the current document with a new filename.
Ctrl + P Print the current document.
Ctrl + Shift + P Print preview.
Ctrl + W Close the current document.
Ctrl + Q Quit Gedit.

Shortcuts for editing documents:
Ctrl + Z Undo the last action.
Ctrl + Shift + Z Redo the last undone action .
Ctrl + X Cut the selected text or region and place it on the clipboard.
Ctrl + C Copy the selected text or region onto the clipboard.
Ctrl + V Paste the contents of the clipboard.
Ctrl + A Select all.

Shortcuts for showing and hiding panes:
F9 Show/hide the side pane.
Ctrl + F9 Show/hide the bottom pane.

Shortcuts for searching:

Ctrl + F Find a string.
Ctrl + G Find the next instance of the string.
Ctrl + Shift + G Find the previous instance of the string.
Ctrl + K Interactive search.
Ctrl + H Search and replace.
Ctrl + Shift + K Clear highlight.
Ctrl + I Goto line.

Shortcuts for tools:
Shift + F7 Check spelling (with plugin).
Alt + F12 Remove trailing spaces (with plugin).
Ctrl + T Indent (with plugin).
Ctrl + Shift + T Remove Indent (with plugin).
F8 Run "make" in current directory (with plugin).
Ctrl + Shift + D Directory listing (with plugin).

Shortcuts for help:
F1 Open gedit's user manual.