The treble clef defines the pitch range usually played by violins or sung by female voices as the tonal scope of a stave. This also corresponds to the pitch range of the ukulele (with the exception of the baritone). Therefore, regardless of the tuning of the instrument, pieces for the ukulele are written in the treble clef.

The treble clef symbol begins at the second stave line (counted from below). On this line, the note G' (G4) is placed, therefore the treble clef is also called G-clef.

G' (G4) belongs to the one-lined octave that starts with C' (C4, middle C) on the first ledger line below the stave.

The next higher octave, the two-lined octave, begins with C'' (C5), situated in the space between the 3rd and 4th stave line.

Notes in this system below middle C pertain to the small octave. They can be played only on the 4th string of an ukulele in linear tuning or on a baritone ukulele.