A piano sonata is a sonata written for unaccompanied piano. Piano sonatas are usually written in several movements, usually three or four, occasionally just one or two. The first movement, and often other movements, is usually composed in sonata form.

The piano sonata first became prominent in the Classical era, when the piano displaced the earlier harpsichord and sonata form rose to prominence as a principle of musical composition. All three of the great Classical era composers, Joseph Haydn, Wolfgang Amadeus Mozart, and Ludwig van Beethoven wrote many piano sonatas.

The 32 sonatas of Beethoven are widely considered as the pinnacle of piano sonata composition; they include the Pathetique Sonata, the Moonlight Sonata, and many more.

In the Romantic era, piano sonatas continued to be composed, though the form took on a somewhat academic tinge and competed with shorter genres more compatible with Romantic compositional style. Piano sonatas continued to be written through the 20th century and up to the present day.