AIO, AEO, GEO, LLMO and SEO: what they mean and which one you need

AIO, AEO, GEO and LLMO are all names for getting your business found and recommended in AI-powered search, and they overlap heavily with SEO. SEO is about ranking in search results. AEO is about being the direct answer to a question. GEO and LLMO are about being cited or recommended by AI assistants such as ChatGPT, Gemini and Copilot. AIO, short for AI optimisation, is the umbrella term that covers all of this.

If the acronyms make your head spin, you’re not alone. The good news is that you don’t need five strategies. You need one joined-up plan that covers the foundations, the way you write and what other people say about you.

The terms, one by one

SEO: search engine optimisation

SEO is the practice of making your website easy for search engines to find, understand and rank. It covers technical health (speed, crawlability, mobile), content that matches what people search for, and links and mentions from other websites. It’s been around since the 1990s, and it’s still the foundation everything else is built on.

AEO: answer engine optimisation

AEO focuses on being the direct answer to a question, not just a link in a list. It grew out of featured snippets and voice assistants, and now applies to Google’s AI Overviews and AI Mode. In practice, it means answer-first writing, clear headings that match real questions, and facts that are specific and up to date. Our AEO guide goes into detail.

GEO: generative engine optimisation

The term GEO comes from a 2023 research paper by academics at Princeton and other universities, who tested which kinds of content changes made a source more likely to be cited in AI-generated answers. Adding statistics, quotations and references to sources all helped. Today, GEO usually means getting your business cited or recommended by ChatGPT, Gemini, Copilot, Claude and Perplexity. That depends heavily on what other websites say about you. Read our GEO guide for the full plan.

LLMO: large language model optimisation

LLMO describes the same goal as GEO from a different angle: influencing how large language models, the technology behind AI assistants, describe your business. You’ll also see “AI SEO”, “AI search optimisation” and “LLM SEO”. For practical purposes, treat them all as GEO.

AIO: AI optimisation

AIO is the broadest term, covering anything that helps your business show up well in AI-powered search and assistants. Confusingly, some people use AIO to mean “AI Overviews optimisation”, which is optimising specifically for Google’s AI summaries. If someone uses the term, it’s worth asking which they mean.

How the terms compare

Term	Main goal	Where it shows up	How you can measure it
SEO	Rank in search results	Google and Bing results pages	Search Console, Bing Webmaster Tools, rankings
AEO	Be the direct answer	AI Overviews, AI Mode, featured snippets, voice	Search Console’s Generative AI report, snippet tracking
GEO / LLMO	Be cited and recommended	ChatGPT, Gemini, Copilot, Claude, Perplexity	AI referral traffic in analytics, Bing AI Performance, manual checks
AIO	All of the above	Every AI-powered search experience	A mix of the above

What Google says

Google has been consistent on this. In 2025, Google’s Gary Illyes reportedly told a Search Central event: “To get your content to appear in AI Overview, simply use normal SEO practices. You don’t need GEO, LLMO or anything else.”

Google’s 2026 guide to its generative AI features says the same thing at more length. It opens with “The best practices for SEO continue to be relevant”, and says you don’t need special AI files, special markup, content chopped into small chunks or writing styled “just for generative AI search”.

That doesn’t make the new terms meaningless. Google is only one part of the picture. ChatGPT runs its own search crawler, Copilot is built on Bing, and research shows that what the wider web says about you strongly affects which brands AI assistants mention. In Ahrefs’ study of 75,000 brands, mentions of a brand around the web were more closely linked with appearing in AI Overviews than backlinks were.

So which one do you need?

For most small and medium-sized businesses, the answer is one plan that covers three layers:

1. Foundations (SEO). A fast, secure website that search engines and AI crawlers can access, with a clear structure and accurate business details. Without this, nothing else works.
2. Content (AEO). Pages that answer your customers’ real questions directly, with specific facts, real examples and named, credible authors.
3. Reputation (GEO). Genuine reviews, mentions in respected publications and directories, and a consistent description of your business everywhere it appears.

If your website is new or has technical problems, start with layer one. If it’s healthy but you never appear in AI answers, layers two and three are where the gains are.

Watch out for

• Acronym selling. If an agency offers SEO, AEO, GEO and AIO as four separate packages, ask what each one actually involves. Most of the work overlaps.
• Guaranteed AI placements. Nobody controls what AI assistants say. Be wary of anyone who promises you’ll be “the answer in ChatGPT”.
• Magic files. llms.txt files and AI-only versions of pages won’t fix weak content. Google says it doesn’t use them. We explain more in our llms.txt guide.
• Fake mentions. Planting reviews or recommendations breaks UK consumer law and Google’s policies, and AI systems are getting better at spotting them.

Ready for some help?

Want a plain-English view of where you stand in search and AI answers? Book a free chat and we’ll check how Google, ChatGPT, Gemini and Copilot see your business today. You can also see how our AEO, GEO and SEO services fit together.