In a Smart campaign, a keyword theme isn't one keyword. It stands for a family of similar searches: Google's example is the theme bakery, which can show your ad on bakery near me, local bakery and cake shop. Negative keyword themes don't expand like that. They block one exact term, and they block it inside longer searches too.
Google's Smart campaign API guide says a negative keyword theme behaves like a negative phrase match keyword. So if you sell burgers and add burger as a negative theme, you've also blocked burger near me and best burger restaurant. Negate the search you don't want, such as burger recipes, not the product.
How it happened on the call
On a mentoring call, the owner of a halal restaurant in the UK was running Smart campaigns. Their themes included both burger and burger near me. We said the single word was too vague to target, since someone searching burger could want a recipe or a picture, and that burger near me was the version worth paying for.
We'd also said to move the single words out of targeting and into negative themes. By the end of the call, burger was on the negative list. For a restaurant that sells burgers, that switched off the burger searches it wanted. The fix we gave: take burger off the negatives, target burger restaurants near me, and negate the searches that aren't diners, like burger recipes or frozen burger patties.
The same test applies to every negative. Words a halal restaurant never wants, like pork or alcohol, are safe as one word. A cuisine word close to the menu, which they'd excluded too, can cut out people who would happily eat there.
The matching rules
- Keyword themes expand. One theme covers multiple similar words and phrases. Google suggests 7 to 10 themes, each up to 20 characters, with no punctuation, URLs or phone numbers. Too many themes can mean less relevant searches.
- Negative themes don't. A negative theme targets only the exact term, like a negative phrase match: any search with those words in that order is blocked, whatever else it contains.
- Close variants slip through. Negative themes don't match close variants, so a negative for burger may still let burgers near me through. A negative can leak and block at the same time.
- Start from real searches. If many search terms are a poor fit, fix the themes. If only a few are, add those individual terms to negative themes from the search terms report.
Google also warns that too many negative themes can mean your ads reach fewer customers.
Make the ad match the search
The same call found an ad with only 3 headlines, none of which mentioned the restaurant's 3,000 reviews or its local ranking. A Smart campaign ad can take 3 to 15 headlines of up to 30 characters and 2 to 4 descriptions. Write headlines for the dishes people actually search for, so someone searching burger near me sees burgers in the ad.
If you run a Smart campaign today
Google Ads Help says Smart campaigns can only be created in Smart Mode, and in the Google Ads API, creating them is no longer supported from September 23, 2026. Existing Smart campaigns keep serving and can still be edited, so the theme rules above still apply to every one that's running.
The takeaways
- A keyword theme covers a family of similar searches. A negative theme blocks one exact term.
- Negative themes behave like negative phrase match, so one word blocks every search containing it.
- Never add a product you sell as a one word negative. Negate the wrong intent, like recipes.
- Negative themes don't match close variants, so check the search terms report after any change.
- Use more of the 15 headlines, and name the dishes or services people search for.
Common questions
How do keyword themes work in Google Ads Smart campaigns?
A single keyword theme represents multiple similar words and phrases. Google's example is the theme bakery, which makes an ad eligible for searches like bakery near me, local bakery and cake shop. Google suggests 7 to 10 themes, each up to 20 characters with no punctuation, URLs or phone numbers.
How do negative keyword themes match searches?
Google's Smart campaign API documentation says a negative keyword theme only negatively targets the exact given term, and that this is equivalent to a negative phrase match keyword. So the ad won't show on searches containing those words in that order, even with extra words around them.
Does a negative keyword theme block plurals and misspellings?
Not necessarily. Google says negative keyword themes don't match close variants, so ads might still show on searches that contain close variations of the negative theme. A negative for burger can still let burgers near me through.
How many headlines can a Smart campaign ad have?
Between 3 and 15 headlines of up to 30 characters, and between 2 and 4 descriptions of up to 90 characters. Google also creates and tests alternate ads from your business information and website.
Can I still create a Smart campaign?
Google Ads Help says Smart campaigns can only be created in Smart Mode. In the Google Ads API, creating Smart campaigns is no longer supported from September 23, 2026, while existing Smart campaigns keep serving and can still be updated. Newer API versions can convert a Smart campaign into a draft Performance Max campaign.