B-flat minor

B♭ minor or B-flat minor is a minor scale based on B-flat, consisting of the pitches B♭, C, D♭, E♭, F, G♭, and A♭. Its key signature has five flats. The harmonic minor scale would use an A♮ instead of A♭.

Its relative major is D-flat major, and its parallel major is B-flat major. Its enharmonic equivalent is A-sharp minor.

B-flat minor is traditionally a 'dark' key. Important oboe solos in this key in the orchestral literature include the second movement of Tchaikovsky's Symphony No. 4, which depicts "the feeling that you get when you are all alone", in Tchaikovsky's words. Tchaikovsky's Piano Concerto No. 1 is also in B-flat minor. An Alpine Symphony by Richard Strauss begins and ends in B-flat minor.

The old valveless horn was barely capable of playing in B-flat minor; the only example found in 18th-century music is a modulation that occurs in the first minuet of Franz Krommer's Concertino in D major, Op. 80.

In classical music