Sinfonia in D major, BWV 1045, sometimes referred to as a violin concerto movement (Konzertsatz), is an orchestral work for solo violin, three trumpets, timpani, two oboes, strings and continuo, by Johann Sebastian Bach.

[1] A late work composed in Leipzig between c. 1742 and 1746,[2] surviving only as a fragment,[3][4] the movement is a sinfonia of an otherwise lost cantata.

[5][6][7] In particular, the piece ends abruptly, with the last two bars (151 and 152) appearing in someone else's hand and attached as a separate page at the end of the manuscript, which is otherwise in Bach's hand.

The work features a highly virtuosic concertato part with extensive chordal and arpeggiated passages and at one point reaches an "unusual high for Bach's violin music".