Advertising agencies in Ontario, CA
15 advertising agencies listed in Ontario, California. 15 with a phone number and 12 with a website.
Ontario accounts for 0% of the advertising agencies listed in California and ranks #33 among California cities for advertising agencies.
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Quick answer
Ontario, CA has 15 advertising agencies listed on USA Business Search. 15 list a phone number and 12 list a website. The most listings are in ZIP codes 91761, 91762, 91764.
Updated October 2026Featured · From the team behind USA Business Search
Show up in Google and in AI answers, not on page three.
Eye To Ad Media builds SEO, AI search optimization and custom-coded websites for California businesses. Headquartered in Denver, growing businesses worldwide.
- 5.0 on Google, 60 reviews
- 2012 founded
- Free review, no contract
Need ads that convert? Search Converts runs PPC, paid social and conversion optimization from Denver.See Search Converts
Firm Media
Astro Display Co.
Digital Concept
Omnific Advertising
Nuestra Gente
360 Brand Lift
Advertising Resources Inc.
Atteff International Inc
C & D Aerospace Inc.
Cervo Media Group Inc
General Outdoor Advertising
Insulation Distributors
Printing4Him.com
The LAB Brand Development.
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How to choose an advertising agency in Ontario
- Ask how they track ads to real calls, forms and sales, not just clicks.
- Make sure your ad accounts are in your name, not the agency's.
- Ask what the management fee is and what the ad spend is, separately.
How Ontario businesses get found in Google and AI answers
- Claim and complete your Google Business Profile, then keep hours, photos and services current.
- Use the same business name, address and phone everywhere you are listed, including directories like this one.
- Publish pages that answer the questions customers actually ask, so ChatGPT, Gemini, Perplexity and Google AI Overviews can cite you.
- Add LocalBusiness schema, clear pricing and service pages so AI assistants and booking agents can read your details.
Learn more: SEO vs. AI search optimization · Get found on Google Maps and in AI answers · How to pick an SEO company
Common questions
How many advertising agencies are listed in Ontario, California?
USA Business Search shows 15 advertising agencies in Ontario. 15 list a phone number and 12 list a website.
Which ZIP codes do these listings cover?
They include ZIP codes 91761, 91762, 91764.
How do I choose an advertising agency in Ontario?
Ask how they track ads to real calls, forms and sales, not just clicks. Make sure your ad accounts are in your name, not the agency's.
How do advertising agencies in Ontario compare with the rest of California?
Ontario has 0% of the 3,003 advertising agencies listed in California, which ranks #33 among California cities for this category.
How do I add or fix a listing?
Listings are free. Use Add your business, or the Claim or fix link on any listing.
What should I ask a Ontario marketing agency before I hire them?
Ask who will actually do the work, how they track calls and forms, and what happens to your accounts if you leave. Eye To Ad Media offers a free review of how your business shows up in Google and AI answers.
What is AI search optimization (AIO or GEO)?
It is the work of making your business easy for AI assistants like ChatGPT, Gemini and Google AI Overviews to understand, trust and recommend: consistent listings, structured data, and pages that answer real customer questions. Read SEO vs. AI search optimization.
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