The Internet Corporation for Assigned Names and Numbers (ICANN /ˈaɪkæn/ EYE-kan) is a nonprofit organization that is responsible for coordinating the maintenance and methodologies of several databases, with unique identifiers, related to the namespaces of the Internet - and thereby, ensuring the network's stable and secure operation.

Most visibly, much of its work has concerned the Internet's global Domain Name System, including policy development for internationalization of the DNS system, introduction of new generic top-level domains (TLDs), and the operation of root name servers. The numbering facilities ICANN manages include the Internet Protocol address spaces for IPv4 and IPv6, and assignment of address blocks to regional Internet registries. ICANN also maintains registries of Internet protocol identifiers.

ICANN performs the actual technical maintenance work of the central Internet address pools and DNS Root registries pursuant to the IANA function contract.

ICANN's primary principles of operation have been described as helping preserve the operational stability of the Internet; to promote competition; to achieve broad representation of the global Internet community; and to develop policies appropriate to its mission through bottom-up, consensus-based processes.