The Adagio in E major for Violin and Orchestra, K. 261, was composed by Wolfgang Amadeus Mozart in 1776. It was probably a replacement movement for the original slow movement of his Violin Concerto No. 5 in A. It is believed that Mozart wrote it specifically for the violinist Antonio Brunetti, who complained that the original slow movement was "too artificial."^[1] The work is scored for solo violin, two flutes, two horns and strings.

It is one of the few compositions Mozart wrote in the key of E major: Piano Trio No. 4, K. 542; the incomplete Horn Concerto, K. 494a; the incomplete fugue, Anh. C27.10.