If you're running campaigns on Google Ads and want to scale your reach to new high-converting audiences, lookalike segments are one of the most effective tools in your targeting toolbox. These AI-powered segments allow you to find new potential customers who "look like" your best existing ones — based on Google’s real-time behavioural and intent data.

1. In this blog, we’ll walk you through:
2. What lookalike segments are,
3. How they work in the current Google Ads ecosystem,
4. A step-by-step guide to creating them, and
5. Best practices to get the most out of them in 2025.


What Are Lookalike Segments in Google Ads?

Lookalike segments (formerly known as "similar audiences") help advertisers target users who share similar characteristics and online behaviors as people in your first-party audience lists, such as:

- Website visitors,
- Past customers,
- YouTube subscribers,
- App users, or
- Uploaded customer data (Customer Match).

These segments are dynamically created by Google and powered by machine learning. They're especially useful for expanding reach in performance-driven campaigns like Search, Display, Video, and Performance Max.

📝 Note: Google Ads began sunsetting “Similar Audiences” in 2023 and fully transitioned to automated lookalike functionality within optimized targeting and audience expansion settings.


How Lookalike Segments Work in 2025

Instead of manually adding similar audiences, Google now uses your seed audience (e.g., Customer Match list) and applies automated expansion during campaign targeting. You no longer have to build the lookalike segment manually — the system does it behind the scenes based on your signals and goals.

To use this feature, you must:

- Have a strong first-party data list (email list, site visitors, app users, etc.),
- Enable optimized targeting (for Display, Discovery, or Video),
- OR run Performance Max campaigns, which automatically incorporate lookalike expansion.


How to Create and Use Lookalike Segments:

Here’s how to activate lookalike targeting in Google Ads using the new setup:

Step 1: Upload or Build a Seed Audience
Go to Tools & Settings → Shared Library → Audience Manager.
- Choose Customer Lists, Website Visitors, or App Users.
- Upload your audience or create a segment using GA4.

Step 2: Create or Edit a Campaign
When creating a new campaign (or editing an existing one), go to the Audience segment section.

Step 3: Enable Optimized Targeting
In Display, Discovery, or Video campaigns, ensure that Optimized Targeting is turned ON.
- This setting allows Google to automatically expand your reach to users similar to your existing audience.

⚠️ Tip: If you're using Performance Max, optimized targeting is enabled by default — just make sure you're feeding it with high-quality audience signals.

Step 4: Monitor & Optimize
Go to your Audience Insights under Tools & Settings → Audience Manager to view the performance of your segments.
- Use Conversion Value, CTR, and Cost per Conversion to evaluate how well your lookalike reach is performing.


Tips to Improve Lookalike Performance

- Use high-quality source lists: The more engaged and recent your audience data is, the more accurate Google’s modelling will be.
- Segment your data: Instead of uploading one large customer file, try breaking it into:
- High LTV customers,
- Recent converters,
- Abandoned cart users.
- Layer audience signals in Performance Max: Include Customer Match, website visitors, and YouTube viewers for stronger predictive modelling.
- Use exclusions: Prevent waste by excluding people who’ve already converted.


Start small, test with high-quality source lists, and let Google’s machine learning do the heavy lifting to find new, conversion-ready users.

Need help building your seed audiences or designing a high-performing Performance Max strategy? Drop us a line — we’d love to help you scale smarter.