In music, a whole tone scale is a scale in which each note is separated from its neighbors by the interval of a whole step. There are only two whole tone scales, both hexachords, each using half of the pitches in the chromatic scale:

• {C, D, E, F#, G#, A#}

• {B, Db, Eb, F, G, A}.

When one of these scales is played on a piano, starting from a low octave and moving up to a high octave, while at the same time pressing the sustain pedal, the result is a "dreamy" sound, such as are used in movies to signal the change from "reality" to a dream, or back from the dream to reality.

Claude Debussy and other Impressionist composers made extensive use of whole tone scales; since they are symmetrical, whole tone scales don't give a strong impression of the tonic or tonality. The whole tone scale was also used by Alban Berg in his Violin Concerto, and by Bela Bartók in his String Quartet No. 5. Ferruccio Busoni used the whole tone scale in the right hand part of the "Preludietto, Fughetta ed Esercizio" of his An die Jugend.

The whole tone scale is interval cycle 2, or C2. Since there are only two transpositions of the whole tone scale it is either C2⁰ or C2¹. The whole tone scale is also maximally even and may be considered a generated collection.

Most interesting, the raga Sahera in Hindustani music uses the same intervals as the whole-tone scale. Ustad Mehdi Hassan has performed this raga.