Johann Georg Albrechtsberger (3 February 1736 – 7 March 1809) was an esteemed Austrian composer, organist, and music theorist, celebrated for his expertise in counterpoint and composition theory during the Classical period. Born in Klosterneuburg, near Vienna, he initially studied music at Melk Abbey and philosophy at a Benedictine seminary in Vienna. His early education included classmates like Michael Haydn and Franz Joseph Aumann. Albrechtsberger's career included positions as an organist in Raab, Hungary, and Maria Taferl, Austria, before becoming Thurnermeister at Melk Abbey. In 1772, he was appointed organist to the court of Vienna and later became the Kapellmeister of St. Stephen's Cathedral in Vienna in 1792.

Albrechtsberger was a prolific composer, known for his church music, orchestral works, and keyboard pieces, although his compositions are not frequently performed today. Notably, he composed a Concerto for Alto Trombone and Orchestra in B♭ Major, a significant work for the trombone repertoire, and a Concerto for the Mandola, Op. 27. His compositions also include preludes, fugues, and sonatas for piano and organ, as well as string quartets, with many works preserved in manuscript form at the Vienna Gesellschaft der Musikfreunde.

His influence extended beyond his compositions, as he was a mentor to numerous prominent composers, including Ludwig van Beethoven, whom he taught counterpoint and fugue. Albrechtsberger's theoretical writings and pedagogical methods left a lasting impact on 19th-century composition, with his treatises on harmony and counterpoint remaining highly regarded. He was also a friend of Haydn and Mozart. Albrechtsberger passed away in Vienna and was buried in St. Marx cemetery.