Johann Sebastian Bach's chorale cantata cycle is the year-cycle of church cantatas he started composing in Leipzig from the first Sunday after Trinity in 1724. It followed the cantata cycle he had composed from his appointment as Thomaskantor after Trinity in 1723.
Bach's second cantata cycle is commonly used as a synonym for his chorale cantata cycle, but strictly speaking both cycles overlap only for 40 cantatas. Two further chorale cantatas may belong to both cycles: the final version of Christ lag in Todes Banden, BWV 4, and the earliest version of Ein feste Burg ist unser Gott, BWV 80; it is, however, uncertain whether these versions were first presented in Bach's second year in Leipzig. Bach composed a further 13 cantatas in his second year at Leipzig, none of them chorale cantatas, although two of them became associated with the chorale cantata cycle. After his second year in Leipzig, he composed at least eight further cantatas for inclusion in his chorale cantata cycle.
Around the start of the Bach Revival in the 19th century, almost no manuscripts of Bach's music remained in St. Thomas in Leipzig, apart from an incomplete chorale cantata cycle. In Leipzig the chorale cantatas were, after the motets, the second most often performed compositions of Bach between the composer's death and the Bach Revival. Philipp Spitta, in his 19th-century biography of the composer, praised the chorale cantatas, but failed to see them as a cycle tied to 1724–25. It took about a century after Spitta before Bach's cantata cycles were analysed in scholarly literature, but then Bach's ambitious project to write a chorale cantata for each occasion of the liturgical year was characterized as "the largest musical project that the composer ever undertook".