NATO Secretary-General Anders Fogh Rasmussen, speaking after a meeting of NATO defense ministers, said the teams would not only protect the alliance's own networks but those of allies.
"They come without warning, from anywhere in the world," he said. "And they can have devastating consequences.
"We are all closely connected. So an attack on one ally, if not dealt with quickly and effectively, can affect us all. Cyberdefense is only as effective as the weakest link in the chain. By working together, we strengthen the chain."
Rasmussen said the alliance dealt with more than 2,500 "significant cases" of cyberattack last year alone but security was not compromised.
The cyber quick-reaction teams should be fully operational but October for the NATO network and for networks of member states that request help.
"Cyberattacks do not stop at national borders," he said. "Our defenses should not, either."
Additional cyberdefense measures will be discussed by ministers next week.