In classical music, a piano quintet is a work of chamber music written for piano and four other instruments, most commonly (since 1842) a string quartet (i.e., two violins, viola, and cello). The term also refers to the group of musicians that plays a piano quintet. The genre flourished during the nineteenth century.

Until the middle of the nineteenth century, most piano quintets were scored for piano, violin, viola, cello, and double bass. Following the success of Robert Schumann's Piano Quintet in E♭ major, Op. 44 in 1842, which paired the piano with a string quartet, composers increasingly adopted Schumann's instrumentation, and it was this form of the piano quintet that dominated during the second half of the nineteenth century and into the twentieth century.

Among the best known and most frequently performed piano quintets, aside from Schumann's, are Schubert's Trout quintet and the piano quintets of Johannes Brahms, César Franck, Antonín Dvořák and Dmitri Shostakovich.

While the related chamber music genres of the piano trio and piano quartet were established in the eighteenth century by Mozart and others, the piano quintet did not come into its own until the nineteenth century. Its roots extend into the late Classical period, when piano concertos were sometimes transcribed for piano with string quartet accompaniment.

Although Luigi Boccherini composed quintets for piano and string quartet, before 1842 it was more common for the piano to be joined by violin, viola, cello and double bass. Among the best known quintets for this combination of instruments are Franz Schubert's "Trout" Quintet in A major (1819) and Johann Nepomuk Hummel's Piano Quintet in E-flat minor, Op.87 (1802). Other piano quintets using this instrumentation were composed by Jan Ladislav Dussek (1799), Ferdinand Ries (1817), Johann Baptist Cramer (1825, 1832), Henri Jean Rigel (1826), Johann Peter Pixis (ca.1827), Franz Limmer (1832), Louise Farrenc (1839, 1840), and George Onslow (1846, 1848, 1849).

Mozart (in 1784) and Ludwig van Beethoven (in 1796) each composed a quintet for piano and winds, scored for piano, oboe, clarinet, horn, and bassoon, that are sometimes referred to as piano quintets.

In the middle of the 19th century, Robert Schumann's Piano Quintet in E♭ major, Op. 44 (1842), composed for piano with string quartet, helped establish that combination of instruments as the typical model for the piano quintet. Schumann's choice of scoring reflected developments in musical performance and instrumental design.

By midcentury, the string quartet was regarded as the most prestigious and important chamber music genre, while advances in the design of the piano had expanded its power and dynamic range. Bringing the piano and string quartet together, Schumann's piano quintet took full advantage of the expressive possibilities of these forces in combination, alternating conversational passages between the five instruments with passages in which the combined forces of the strings are massed against the piano. In Schumann's hands, the piano quintet became a genre "suspended between private and public spheres" alternating between "quasi-symphonic and more properly chamber-like elements"—well suited to an era when chamber music was increasingly being performed in large concert halls rather than at private gatherings in intimate spaces.