AWS Organizations centralize management of multiple accounts. Organizational Units (OUs) hierarchy. Service Control Policies (SCPs) enforce guardrails — deny specific APIs across accounts. Consolidated billing aggregates costs. Cross-account roles enable delegated access without credentials sharing.
Account structure strategy: separate production, development, security audit accounts. Delegated Admin accounts for services. Best practices: never use root credentials, enable CloudTrail per account, enable GuardDuty, enable Config rules.