Co-citation is when two entities, such as brands or pages, are mentioned or cited together by a third source. Frequent co-citation suggests they are related.
What is Co-citation?
Co-citation occurs when two entities, such as brands or web pages, are mentioned or cited together by a third source. The more often two entities are co-cited, the more closely related they appear to be. In SEO and AI search, co-citation describes how being named alongside other brands in a category helps search engines and language models associate you with that category.
The concept comes from bibliometrics. Henry Small and Irina Marshakova independently introduced co-citation analysis in 1973 to measure how related two scientific papers are based on how often later papers cite both. SEO practitioners later borrowed the idea to describe relationships between sites, brands and topics, including through unlinked mentions.
How it works
The basic logic is simple:
- A third-party article lists your brand alongside two well-known competitors as leading cloud security platforms (an illustrative example).
- Many other articles, reviews and threads repeat similar groupings.
- Systems that analyze text, whether a search engine or a language model in training, learn that your brand belongs in that set.
Co-citation is related to, but different from, these signals:
- Links. A link is a direct reference; co-citation can work without links.
- Co-occurrence. Terms appearing close together in text, such as your brand name near “SOC 2 automation.”
- Entity relationships. Structured knowledge, such as a knowledge graph entry that lists your category.
From SEO to AEO and GEO
In classic SEO, co-citation was mostly discussed as a supporting signal for link analysis and relevance, and its exact role in Google’s algorithms was never confirmed. In AEO and GEO, the idea becomes more practical. When a buyer asks “best API security tools,” an AI engine answers with a short list. Those lists tend to mirror the groupings that appear repeatedly in the sources it retrieves and the text it learned from.
What carries over: earning mentions on relevant, credible sites. What changed: unlinked mentions and inclusion in comparison lists matter more, because AI answers name brands rather than ranking URLs. The goal is to be co-cited with the right peers, in the right category, in sources AI engines actually use.
What to do about it
- Audit AI shortlists. Run category prompts in several engines and note which competitors appear with or without you.
- Find the sources. Check which pages engines cite for those prompts; they are your co-citation targets.
- Pitch for inclusion. Offer authors accurate product details, screenshots and a briefing for comparison articles.
- Build review presence. Category pages on review sites group vendors, which creates co-citation.
- Publish fair comparisons. “[Competitor] alternatives” pages that treat rivals accurately are often cited.
- Keep category language consistent. Describe your category the same way everywhere so associations stay clear.
Common mistakes
- Buying placement on spammy listicles. Low-quality lists add little and can harm trust.
- Being co-cited in the wrong category. If articles group you with consumer tools, models may too.
- Treating co-citation as a confirmed ranking factor. It is a useful model, not a documented metric.
Related terms
- Brand Mentions
- Unlinked Brand Mentions
- AI Share of Voice
- Entity Optimization
- Topical Authority
- Guide: How AI engines cite sources
Sources
- Co-citation, Wikipedia (history and definition)
- What is a co-citation?, Ahrefs SEO Glossary
- Understanding news topic authority, Google Search Central Blog (on how citation by other publishers signals influence)
Frequently asked questions
What is the difference between co-citation and co-occurrence?
In SEO usage, co-citation usually means two sites or brands are referenced by the same third source. Co-occurrence means words or entities appear near each other in text, such as a brand name next to a category term. The two are related and often discussed together; neither is a confirmed, named Google ranking factor.
Does co-citation affect AI answers?
Plausibly, though no vendor documents it directly. Language models learn associations from text, so a brand that is repeatedly named alongside recognized category leaders is more likely to be recalled in category answers. Retrieval-based answers also often draw on listicles and comparisons where co-citation happens.
How can a B2B SaaS company earn co-citations?
Get included in credible comparison articles, analyst reports, review site category pages, conference agendas, podcasts and community discussions where competitors are also named. Publish honest comparison content yourself. Avoid paying for placement on low-quality list sites, which adds little and can look manipulative.
Guides that cover Co-citation
-
AI search monitoringWhy You Should Monitor Brand Mentions in AI Search Results
Stop chasing blue links. Learn why monitoring brand mentions in AI search results is critical for visibility in the 'zero-click' era of Generative AI.
