Basso continuo is a musical term that refers to a bass line and keyboard part that provide a harmonic framework for a piece of music. It is also known as "continuous bass" or "through bass". Basso continuo parts were almost universal in the Baroque era (1600-1750) and provided the harmonic structure of the music by supplying a bassline and a chord progression. The composition of the continuo group is often left to the discretion of the performers or conductor, and practice varied enormously within the Baroque period. At least one instrument capable of playing chords must be included, such as a harpsichord, organ, lute, theorbo, guitar, regal, or harp. In addition, any number of instruments that play in the bass register may be included, such as cello, double bass, bass viol, or bassoon. Sometimes instruments are specified by the composer.

The bass line is written out exactly, while the chordal instrument(s) improvise an accompanying harmony part based upon the implied underlying chord progression. Figured bass is a system of numbers and symbols written beneath the continuo line that indicated the harmonies that were to be improvised by the instrument playing the chords, usually the harpsichord.

Basso continuo is an essential structural and identifying element of the Baroque period, but it continued to be used in many works, mostly sacred choral works, of the classical period (up to around 1800). An example is C. P. E. Bachs Concerto in D minor for flute, strings, and basso continuo.

The instrumentalists playing the continuo part, if more than one, are called the continuo group. The titles of many Baroque works make mention of the continuo section, such as J. S. Bach’s Concerto for Two Violins, Strings and Continuo in D Minor.