.aero (derived from aeronautics) is a generic top-level domain (gTLD) used in the Domain Name System of the Internet. It is the first sponsored top-level domain based on a single industrial theme. The aero domain is reserved for companies, organizations, associations, government agencies, and individuals in aviation-related fields. It was created in 2002 and is operated by SITA. SITA created and operates the Dot Aero Council.

Two-letter codes under aero are reserved for airlines according to the IATA Airline Designators. While three-letter codes were initially reserved for airports (IATA airport code), they were released for registration by the larger aviation and aerospace community on December 1, 2008.

Domain name registrations are processed via accredited registrars. The largest official .aero registrar is NamesBeyond, operating from the USA and Canada.

The aero domain name was initially approved in 2001 for a 5-year term expiring December 17, 2006 as part of a proof-of-concept of new top-level domains. The agreement was extended in October 2006 for a six month term until June 17, 2007, and continued to be renewed on a June-December six-month cycle through June 17, 2009. In 2009, SITA and ICANN completed a new 10-year sponsorship agreement for the operation of aero.