Franz Schubert's Impromptus are a series of eight pieces for solo piano composed in 1827. They were published in two sets of four impromptus each: the first was published in the composer's lifetime as Op. 90, and the second was published posthumously as Op. posth. 142. They are now catalogued as D. 899 and D. 935 respectively. They are considered to be among the most important examples of this popular early 19th-century genre. The Impromptus are often considered companion pieces to the Six moments musicaux, and they are often recorded and published together.