The Joint Rapid Reaction Force (JRRF) was a capability concept of the British Armed Forces from 1999 to 2010. It was a pool of specialised units from all three armed services tasked with rapid deployment worldwide at short notice. The force was intended to be capable of mounting operations up to medium scale warfighting. It could be employed nationally, or multinationally under the auspices of NATO, the United Nations or any other coalition.

A rapid reaction force / rapid response force (RRF), quick reaction force / quick response force (QRF), immediate reaction force (IRF), rapid deployment force (RDF), or quick maneuver force (QMF) is a military or police unit capable of responding to emergencies in a very short time frame.