An ad group is a container inside a Google Ads campaign that holds a set of related ads and the keywords (or other targeting criteria) that trigger those ads. It sits in the middle of Google’s three-layer account structure: your account holds campaigns, your campaigns hold ad groups, and your ad groups hold the actual ads people see. Understanding how ad groups work is key to keeping your ads relevant and your budget under control.
Where Ad Groups Fit in Your Account
Google Ads is organized into three layers: account, campaigns, and ad groups. Your account stores your login credentials and billing information. Your campaigns each have their own budget and high-level settings that determine where and when your ads can appear. Within each campaign, ad groups let you break things down further by grouping specific ads with specific keywords.
Think of it like a filing cabinet. The account is the cabinet itself. Each campaign is a drawer. Each ad group is a folder inside that drawer, and the ads and keywords inside the folder are the individual documents. This structure lets you control spending at the campaign level while fine-tuning relevance at the ad group level.
What an Ad Group Actually Contains
Every ad group holds two core ingredients: ads and targeting. For Search campaigns, the targeting is a set of keywords, the words and phrases you want to match against what people type into Google. For Display or Video campaigns, targeting might be audience interests, placements on specific websites, or demographic criteria instead of keywords.
Each ad group can hold multiple ads. Google will rotate them and eventually favor the ones that perform best. The limits are generous: you can have up to 50 active text ads per ad group and up to 3 enabled responsive search ads. For image ads, the cap is 300 per ad group. On the targeting side, you can attach up to 20,000 targeting items (keywords, placements, audience lists) to a single ad group.
You can also set a default bid at the ad group level. This is the maximum amount you’re willing to pay per click (or per thousand impressions, depending on your bidding strategy) for everything in that ad group. You can override it for individual keywords, but the ad group bid serves as the baseline.
Why Grouping by Theme Matters
The whole point of an ad group is relevance. When someone searches “compact digital camera,” you want them to see an ad about compact digital cameras, not a generic ad about photography equipment. By organizing your keywords into tightly themed ad groups, you can write ad copy that closely matches what the searcher is looking for.
Google recommends picking a narrow theme for each ad group and building your keywords and ads around it. A camera store, for example, might run a single campaign called “Cameras” but create separate ad groups for digital cameras, compact cameras, and camera accessories. Each ad group gets its own keyword list and its own tailored ads. The result: the person searching for “compact camera deals” sees an ad specifically about compact cameras, which makes them more likely to click.
This tight alignment also improves your Quality Score, Google’s rating of how relevant your ad and landing page are to a given keyword. Higher Quality Scores typically lower your cost per click and give your ads better placement. Stuffing dozens of unrelated keywords into one ad group makes it nearly impossible to write ad copy that speaks to all of them, which drags your Quality Score down and raises your costs.
How to Organize Your Ad Groups
A practical starting point is your own website. If your site has separate pages for different product categories or services, each page can map to its own ad group. The keywords in that ad group would reflect the language on that page, and the ads would link directly to it.
For a plumbing company, that might look like one ad group for “drain cleaning” with keywords like “clogged drain repair” and “drain cleaning service,” and another ad group for “water heater installation” with keywords like “tankless water heater install” and “water heater replacement.” Each ad group gets ads written specifically for that service and pointing to the matching page on the site.
Some advertisers organize by business goal instead. You might have one campaign focused on brand awareness with ad groups built around your brand name and variations, and another campaign focused on conversions with ad groups built around high-intent keywords like “buy,” “hire,” or “near me.”
There’s no single correct structure. The guiding principle is that every keyword in an ad group should make sense alongside every ad in that same ad group. If a keyword feels out of place next to the ad copy, it belongs in a different ad group.
Account Limits to Keep in Mind
Google allows up to 20,000 ad groups per campaign and up to 10,000 campaigns per account. App campaigns and Local campaigns are more restrictive, capping at 100 ad groups per campaign. Across your entire account, you can have up to 5 million targeting items (keywords, placements, and audience lists combined) and up to 4 million ads.
In practice, most advertisers never come close to these limits. A well-organized small business account might have a handful of campaigns with 5 to 15 ad groups each. The limits matter more for large e-commerce sites or agencies managing accounts with thousands of products.
Ad Groups in Different Campaign Types
The concept of an ad group stays the same across campaign types, but what goes inside it changes slightly. In Search campaigns, ad groups revolve around keywords. In Display campaigns, they revolve around audience segments, topics, or specific website placements. In Video campaigns, an ad group contains video ads that share common targeting criteria, and all the video ads within a single ad group must use the same format.
Shopping campaigns work a bit differently. Instead of keywords, your ad groups contain product groups, which are subsets of your product inventory organized by attributes like brand, category, or product type. The ad group still serves the same structural purpose: it lets you group similar items together so you can set bids and monitor performance at a meaningful level.
Regardless of campaign type, the principle holds: keep each ad group tightly focused on one theme so your targeting and your creative stay aligned. That alignment is what makes the difference between ads that feel relevant to your audience and ads that get ignored.