A Rapid Reaction force is a military or police units designed to respond in very short time frames to emergencies. When used in reference to police forces such as SWAT teams, the timeframe is minutes, while in military applications, such as with the use of paratroops or other commandos, the timeframe is hours to days.

Rapid reaction forces are designed to intervene quickly in rather low-intensity conflicts, such as uprisings that necessitate the evacuation of foreign embassies. Because they are usually transported by air, such military units are usually lightly armed, but often extremely well trained to compensate for their lower calibre weapons and lack of heavy equipment like tanks.