Mean Time to Respond (MTTR) is the average time it takes a security team to contain, investigate, and remediate an incident after it has been detected. It is usually measured from the moment an alert is confirmed until the threat is neutralized and recovery actions are complete.
MTTR matters because fast response reduces attacker dwell time, limits data loss, and shortens business disruption. A low MTTR often reflects strong playbooks, clear ownership, and practiced coordination across security, IT, and operations. In real attacks, MTTR shows how quickly teams can isolate compromised accounts, disable malicious access, block command-and-control traffic, and restore safe systems. In defense, organizations track MTTR alongside MTTD to test whether monitoring and incident response are actually improving, not just generating more alerts.