Prelude and Fugue in B minor, BWV 893, is a keyboard composition by Johann Sebastian Bach. It is the 24th and final prelude and fugue in the second book of The Well-Tempered Clavier, a series of 48 preludes and fugues by the composer. It was composed in 1738.
The prelude is in the key of B minor and in the time signature of cut time () (some editions however, including the Altnickol and Tovey editions have it at common time). It is in two voices and has 66 measures. There is rarely any ornamentation in this piece.
The fugue is also in B minor and is in . It is in 3 voices and has 100 measures. It ends with a Picardy third.