Lookalike audience
Updated
A lookalike audience is a group of new people chosen because they resemble a list of existing customers, called the seed list. Google's developer guide (updated 14 Oct 2026) says its lookalike segments are built from first-party data, such as lists of past customers. In the UK, the ICO (2 Apr 2026) says you must have a valid lawful basis to handle personal information.
From March 2026, Google began treating the seed list as a signal rather than a strict limit in Demand Gen campaigns.
The result follows the seed. A seed of brochure requesters looks for people like brochure requesters, not like bookers. Example: a hotel group seeds an audience with past guests who booked suites.
Related: first-party data · intent data · retargeting pixel