Concerto for Bassoon in B-flat major, K. 186e/191

The Bassoon Concerto in B-flat major, K. 191/186e, is a bassoon concerto written in 1774 by Wolfgang Amadeus Mozart. It is the most often performed and studied piece in the entire bassoon repertory. Nearly all professional bassoonists will perform the piece at some stage in their career, and it is probably the most commonly requested piece in orchestral auditions – it is usually requested that the player perform excerpts from the concerto's first two movements in every audition.

Although the autograph score is lost, the exact date of its completion is known: 4 June 1774.

Mozart wrote the bassoon concerto when he was 18 years old, and it was his first concerto for a wind instrument. Although it is believed that it was commissioned by an aristocratic amateur bassoon player Thaddäus Freiherr von Dürnitz, who owned seventy-four works by Mozart, this is a claim that is supported by little evidence. Scholars believe that Mozart may have written five bassoon concertos, but that only the first has survived.