Facebook Ads Interest Targeting: How to Build Audiences That Actually Buy
Interest targeting sounds straightforward: pick interests that match your customer, reach people with those interests. The problem is that "interested in fitness" includes everyone who liked a gym photo once. "Interested in investing" includes people who read one article. Interests measure curiosity, not intent. The skill is picking interests that correlate with actual buying behaviour, and knowing when the algorithm already knows your buyer better than any interest list can.
Read also
The interest quality hierarchy
| Interest quality | Example | Why it works (or not) |
|---|---|---|
| High: Brand-specific interests | "Shopify", "Mailchimp", specific competitor brands | People who use specific tools are buyers, not just curious |
| High: Publication/media interests | "Inc. Magazine", "Entrepreneur" readers | Self-selected as business audience |
| Medium: Behaviour-adjacent interests | "Small business owners", "E-commerce" | Broad but directionally correct |
| Low: Category interests | "Marketing", "Business", "Finance" | Too broad — half the internet qualifies |
| Worthless: Aspirational interests | "Success", "Wealth", "Healthy lifestyle" | No purchasing signal whatsoever |
The layering technique (AND vs OR)
When you add multiple interests in the same interest box, Facebook uses OR logic: it reaches anyone who matches any of those interests. When you use the "Narrow Audience" feature to add a second interest group, Facebook uses AND logic: the person must match interest group 1 AND interest group 2. For example: [Fitness interests] AND [has made an online purchase in the last 30 days] creates a much more qualified audience than fitness interests alone. Use narrow audience to add a purchasing behaviour or income indicator.
When to skip interest targeting entirely
See your Facebook and Google ad results in plain language
No marketing experience needed. Connect your account and know what is working in under 5 minutes.
- Broad targeting (no interests, just age + location) often outperforms interest targeting for campaigns with Advantage+ audience enabled. Let the algorithm find buyers from purchase signals.
- If your pixel has 500+ purchase events in the last 30 days, Lookalike Audiences will outperform interest targeting because they are based on actual buyer behaviour, not self-reported interests.
- Retargeting campaigns should never use interest targeting — you already know exactly who the audience is (website visitors, video viewers, etc.).
The most underused interest targeting technique: targeting competitors by name. If you sell project management software, targeting people interested in "Asana", "Monday.com", or "Trello" reaches people who are already in the buying category for your product. They know the problem exists, they know software solves it — you just need to show them why yours is better.
Questions people ask
How many interests should I add to a Facebook ad set?
For testing: 3-5 related interests in one ad set, then a separate ad set with 3-5 different interests. This lets you compare interest clusters without splitting budget too thin. For scaling: consolidate your winning interests into one broader audience rather than maintaining many small interest segments.
Why does Facebook show my ad to people who do not match my interests?
Because interest targeting is a starting signal, not a filter. Facebook uses your selected interests to find the first batch of people, then expands based on who actually engages with your ad. If people outside your interest set are clicking and buying, Facebook will find more of them. This is by design and is generally beneficial.