B minor is a minor scale based on B, consisting of the pitches B, C♯, D, E, F♯, G, and A. Its key signature has two sharps. Its relative major is D major and its parallel major is B major.

The B natural minor scale is:

Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary. The B harmonic minor and melodic minor scales are:

Christian Friedrich Daniel Schubart (1739–1791) regarded B minor as a key expressing a quiet acceptance of fate and very gentle complaint, something commentators find to be in line with Bach's use of the key in his St John Passion. By the end of the Baroque era, however, conventional academic views of B minor had shifted: Composer-theorist Francesco Galeazzi (1758–1819) opined that B minor was not suitable for music in good taste. Beethoven labelled a B-minor melodic idea in one of his sketchbooks as a "black key".