999: What's Your Emergency? is a British television documentary. Broadcast on Channel 4, the show provides insight into modern Britain through the eyes of the emergency services, using a mixture of fly-on-the-wall footage taken at incidents and retrospective interviews with the people and staff featured. The show is narrated by Hugo Speer, with the exception of Series 2 which was narrated by Julian Barratt.

Series 1 followed police officers, paramedics, firefighters, and call handlers in Blackpool, Lancashire. Series 2 followed paramedics throughout the UK. Series 3 followed police officers, paramedics, and call handlers in Cheshire. From Series 4 to Series 11, the show followed police officers, paramedics, call handlers, and occasionally firefighters in Wiltshire and Northamptonshire. Series 12 onwards has followed police officers and call handlers in South Yorkshire and Northamptonshire police.