GuitarScales is a iOS application for learning guitar scales and memorize the notes on the guitar fretboard. It contains chromatic, Ionian (major), harmonic major, Dorian, Phrygian, Lydian, Mixolydian, Aeolian (minor), Locrian, harmonic minor, major pentatonic, minor pentatonic, blues pentatonic, Hungarian Gypsy, Ukrainian Dorian, Acoustic, Persian, Algerian, Flamenco, Hawaiian, Chinese, Byzantine and Neopolitan scales. Guitar Scales app contains scales for standard, 1/2 step down, 1 step down, standard B, drop D, drop C and drop A tunings. Highlight the whole fretboard to show which notes are within a chosen scale and a some positions (5 positions, 3 notes per string positions, diagonal positions) for each scale. Containing examples of the sound of scale and notes sounds. Optimised for all devices and tablets. Guitar Scales app has right-handed and left-handed modes. It can be useful for both novice guitar players and advanced players.