A lookalike audience is a group of new people that an ad platform picks because they resemble a source audience you give it, such as your buyers, your email list or your highest-value customers. Lookalike audiences are a Meta feature, and TikTok offers a similar option.
On Meta you choose the source, the country and the size, given as a percentage of the country's population. A smaller lookalike sticks closer to the source; a larger one reaches more people with a looser match.
Lookalikes are only as good as their source. A list of repeat buyers or customers with a high order value usually makes a better audience than all site visitors.
- Start from purchase or value data rather than clicks or page views.
- Keep source lists fresh, since an old list describes old customers.
- Test lookalikes against broad targeting: with strong creatives, the algorithm can often find buyers with few restrictions.
Common mistakes: building lookalikes from tiny or low-quality sources, running several overlapping lookalikes so your ad sets compete for the same people, and expecting a lookalike to fix a weak offer or creative.