Tenant ID

A Tenant ID is the globally unique GUID identifying a Microsoft 365 / Entra ID tenant — used in APIs, configurations, and integrations. Format: 00000000-0000-0000-0000-000000000000. Visible in the Entra admin center → Overview, in the Microsoft 365 admin center, and via PowerShell ((Get-MgContext).TenantId). The Tenant ID is permanent and unique across all Microsoft 365 tenants worldwide. It's also called the Directory ID in older docs. Different from the .onmicrosoft.com domain name (which is also tenant-specific but more human-readable). Use the Tenant ID for any programmatic integration where unambiguous tenant identification matters.