Interagency coordination is cooperation between government bodies that share security responsibilities. In cyber security, this usually means military, intelligence, police, civilian regulators, and national cyber agencies working from a shared plan, with clear rules for who detects, decides, contains, and recovers from an incident. Good coordination reduces duplication and prevents gaps between agencies with different legal powers and technical skills.
It matters because major cyber incidents rarely fit inside one institution. An attack on public infrastructure may require threat intelligence from one body, law-enforcement action from another, and operational response from a defense or national cyber command. In defense, coordination supports faster incident handling, clearer escalation paths, and more consistent guidance to affected organizations. When it is weak, agencies can delay action, issue conflicting orders, or miss indicators because information is not shared quickly enough. Effective interagency coordination is therefore a core part of national cyber resilience, not just an administrative detail.