"In Dulci Jubilo"/"On Horseback" is a double A-side single and third overall by English musician Mike Oldfield, released in November 1975 by Virgin Records.

This is an instrumental version of the German traditional Christmas carol of the same name, known best in Britain as "Good Christian Men Rejoice".

Oldfield had recorded an earlier version with Les Penning as the B-side to his previous single, "Don Alfonso", which did not chart.

This version features Penning on two recorders and kortholt, William Murray on snare drum, and Oldfield on acoustic and electric guitars, piano, and ARP string synthesiser.

"On Horseback" features Oldfield on vocals accompanied by a children's chorus, credited as the Penrhos Kids.

On 27 July 2012 at the 2012 Summer Olympics opening ceremony Oldfield performed renditions of Tubular Bells, "Far Above the Clouds" and "In Dulci Jubilo" during a segment about the NHS.

The piece was also used as the theme tune to the BBC cookery show Fanny Cradock Cooks for Christmas.

The video splits the screen up to 9 thumbnail frames, each showing Oldfield or Les Penning playing a different instrument.