The six Cello Suites, BWV 1007 to 1012, are suites for unaccompanied cello by Johann Sebastian Bach. They are some of the most frequently performed and recognizable solo compositions ever written for cello. Bach most likely composed them during the period 1717–23, when he served as a Kapellmeister in Köthen. The title of the Anna Magdalena Bach manuscript was Suites á Violoncello Solo senza Basso (Suites for cello solo without bass).
These suites for unaccompanied cello are remarkable in that they achieve the effect of implied three- to four-voice contrapuntal and polyphonic music in a single musical line. As usual in a Baroque musical suite, each movement is based around a baroque dance type; the cello suites are structured in six movements each: prelude, allemande, courante, sarabande, two minuets or two bourrées or two gavottes, and a final gigue. The Bach cello suites are considered to be among the most profound of all classical music works. Wilfrid Mellers described them in 1980 as "Monophonic music wherein a man has created a dance of God."
Due to the works' technical demands, étude-like nature, and difficulty in interpretation because of the non-annotated nature of the surviving copies, the cello suites were little known and rarely publicly performed until they were revived and recorded by Pablo Casals in the early 20th century. They have since been performed and recorded by many renowned cellists, have also been transcribed for numerous other instruments, and are considered some of Bach's greatest musical achievements.
An exact chronology of the suites (regarding both the order in which the suites were composed and whether they were composed before or after the solo violin sonatas) cannot be completely established. However, scholars generally believe that—based on a comparative analysis of the styles of the sets of works—the cello suites arose first, effectively dating the suites earlier than 1720, the year on the title page of Bach's autograph of the violin sonatas.
The suites were not widely known before the 1900s, and for a long time it was generally thought that the pieces were intended to be studies. However, after discovering Grützmacher's edition in a thrift shop in Barcelona, Spain, at age 13, Catalan cellist Pablo Casals began studying them. Although he later performed the works publicly, it was not until 1936, when he was 60 years old, that he agreed to record the pieces, beginning with Suites Nos. 1 and 2, at Abbey Road Studios in London. By 1939, Casals became the first to record all six suites. Their popularity soared soon after, and Casals' original recording is still widely available and respected today.
The suites have since been performed and recorded by many renowned cellists including Mstislav Rostropovich, Paul Tortelier, and Yo-Yo Ma. Yo-Yo Ma won the 1985 Grammy Award for Best Instrumental Soloist Performance for his album Six Unaccompanied Cello Suites.
Unlike Bach's solo violin sonatas, no autographed manuscript survives, thus ruling out the use of an urtext performing edition. However, analysis of secondary sources, including a hand-written copy by Bach's second wife, Anna Magdalena, has produced presumably authentic editions, although critically deficient in the placement of slurs and other articulation, and devoid of such basic performance markings as bowings and dynamics. As a result, the texts present performers with numerous problems of interpretation.
German cellist Michael Bach has stated that the manuscript of the suites by Anna Magdalena Bach is accurate. The unexpected positioning of the slurs corresponds closely to the harmonic development, and the details of his analysis confirm this.
Recent research has suggested that the suites were not necessarily written for the familiar cello played between the legs (da gamba), but an instrument played rather like a violin, on the shoulder (da spalla). Variations in the terminology used to refer to musical instruments during this period have led to modern confusion, and the discussion continues regarding the instrument "that Bach intended", or even if a particular instrument was indeed intended. Sigiswald Kuijken and Ryo Terakado have both recorded the complete suites on this "new" instrument, known today as a violoncello or viola da spalla; reproductions of the instrument have been made by luthier Dmitry Badiarov.
Bach transcribed at least one of the suites, Suite No. 5 in C Minor, for lute. An autograph manuscript of this version exists as BWV 995.
Using the Bach edition prepared by cellist Johann Friedrich Dotzauer and published by Breitkopf & Härtel in 1826, Robert Schumann wrote arrangements with piano accompaniment for all six Bach cello suites. Schumann's publisher accepted his arrangements of the Bach violin sonatas in 1854, but rejected his Bach cello-suite arrangements. His only cello-suite arrangement surviving is the one for Suite No. 3, discovered in 1981 by musicologist Joachim Draheim in a 1863 transcription by cellist Julius Goltermann.
 It is believed that Schumann's widow Clara Schumann, along with violinist Joseph Joachim, destroyed his Bach cello-arrangement manuscripts sometime after 1860, when Joachim declared them substandard.
 Writing in 2011, Fanfare reviewer James A. Altena agreed with that critique, calling the surviving Bach-Schumann cello/piano arrangement "a musical duckbilled platypus, an extreme oddity of sustained interest only to 19th-century musicologists".
In 1923, Leopold Godowsky composed piano transcriptions of Suites Nos. 2, 3, and 5, in full counterpoint for solo piano, subtitling them "very freely transcribed and adapted for piano".
The cello suites have been transcribed for numerous solo instruments, including the violin, viola, double bass, viola da gamba, mandolin, piano, marimba, classical guitar, recorder, flute, electric bass, horn, saxophone, clarinet, bassoon, trumpet, trombone, euphonium, tuba, ukulele, and charango. They have been transcribed and arranged for orchestra as well.