Most keyboard shortcuts can be customized via Edit → Preferences... → Shortcuts tab (Mac: MuseScore → Preferences... → Shortcuts tab). Below is a list of some of the initial shortcut settings.
Beginning of score: Home
Last page of score: End
Next score: Ctrl+Tab
Previous score: Shift+Ctrl+Tab
Zoom in: Ctrl++ or Ctrl + mouse wheel
Zoom out: Ctrl+- or Ctrl + mouse wheel
Next page: Pg Dn or Shift + mouse wheel
Previous page: Pg Up or Shift + mouse wheel
Next measure: Ctrl+→ (Mac: ⌘+→)
Previous measure: Ctrl+← (Mac: ⌘+←)
Next note: →
Previous note: ←
Note below (within a chord or on lower staff): Alt+↓
Note above (within a chord or on higher staff): Alt+↑
Top note in chord: Ctrl+Alt+↑ (Ubuntu uses this shortcut for Workspaces instead)
Bottom note in chord: Ctrl+Alt+↓ (Ubuntu uses this shortcut for Workspaces instead)
Begin note input mode: N
Leave note input mode: N or Esc
1 ... 9 selects a duration. See also Note input.
Half duration of previous note: Q
Double duration of previous note: W
Voice 1: Ctrl+I Ctrl+1 (Mac ⌘+I ⌘+1)
Voice 2: Ctrl+I Ctrl+2 (Mac ⌘+I ⌘+2)
Voice 3: Ctrl+I Ctrl+3 (Mac ⌘+I ⌘+3)
Voice 4: Ctrl+I Ctrl+4 (Mac ⌘+I ⌘+4)
Pitches can be entered by their letter name (A-G), or via MIDI keyboard. See Note input for full details.
Repeat previous note: R
Raise pitch by octave: Ctrl+↑ (Mac: ⌘+↑)
Lower pitch by octave: Ctrl+↓ (Mac: ⌘+↓)
Raise pitch by semi-tone (prefer sharp): ↑
Lower pitch by semi-tone (prefer flat): ↓
Raise pitch diatonically: Alt+Shift+↑
Lower pitch diatonically: Alt+Shift+↓
Circle through enharmonic notes: J
Rest: 0 (zero)
Add interval above current note: Alt+[Number]
Flip direction (stem, slur, tie, tuplet bracket, etc.): X
Mirror note head: Shift+X
Staccato: Shift+S
Crescendo: <
Decrescendo: >
Staff text: Ctrl+T
System text: Ctrl+Shift+T
Tempo text: Ctrl+Alt+T
Rehearsal Mark: Ctrl+M
Enter lyrics on a note: Ctrl+L
Previous lyric syllable: Shift+Space
Next lyric syllable: if the current and the next syllables are separated by a '-': -, else Space
Move lyric syllable left by 1sp: ←
Move lyric syllable right by 1sp: →
Move lyric syllable left by 0.1sp: Ctrl+←
Move lyric syllable right by 0.1sp: Ctrl+→
Move lyric syllable left by 0.01sp: Alt+←
Move lyric syllable right by 0.01sp: Alt+→
Up to previous stanza: Ctrl+↑ (Mac: ⌘+↑)
Down to next stanza: Ctrl+↓ (Mac: ⌘+↓)
For more lyric shortcuts, see Lyrics.
Navigator: F12 (Mac: fn+F12)
Play Panel: F11 (Mac: fn+F11)
Mixer: F10 (Mac: fn+F10)
Palette: F9 (Mac: fn+F9)
Inspector: F8 (Mac: fn+F8)