Holby City, stylised as Holby Ci⁺y, is a British medical drama television series that airs weekly on BBC One.

The series was created by Tony McHale and Mal Young as a spin-off from the established BBC medical drama Casualty, and premiered on 12 January 1999. It is set in the same hospital as Casualty, Holby General, in the fictional city of Holby, and features occasional crossovers of characters and plots with both Casualty (in episodes broadcast as Casualty@Holby City) and the show's 2007 police procedural spin-off HolbyBlue.

The show follows the lives of medical and ancillary staff at the fictional Holby City Hospital. It began with eleven main characters in its first series, all of whom have since left the show. New main characters have been both written in and out of the series since, with a core of fifteen main actors employed on the serial at any given time.

Thirteen series of Holby City have aired, and a fourteenth has just begun. The show has run for over 500 hour-long episodes. It is filmed at the BBC's Elstree Studios in Hertfordshire, and from 2004 to 2008 featured annual special episodes filmed on location abroad. From October 2010, Holby City moved to high definition broadcasting.