The Symphony No. 15 in G major, K. 124 is a symphony by Wolfgang Amadeus Mozart that was written in Salzburg during the first weeks of 1772. A note on the autograph manuscript indicates that it might have been written for a religious occasion, possibly in honour of the new Archbishop of Salzburg.
The work is scored for two oboes, two horns in G, and strings.
It is in four movements, the first of which has been described as innovative and "daring", in view of its variations of tempo. The last movement is characterised by good humour and frivolity, with "enough ending jokes to bring the house down".