The most-cited domains in ChatGPT are Wikipedia and Reddit: in a Similarweb analysis of roughly 600,000 US ChatGPT citation events from January–February 2026, Wikipedia accounted for 13.15% of citations and Reddit 11.97% — together more than a quarter of all citations. OpenAI's own domain, YouTube, LinkedIn, Reuters, and NIH round out the top ten. These rankings are a snapshot, not a fixed law: they shift with model updates and vary by engine, so treat them as direction, not gospel.
Key takeaways🔗
- Wikipedia is ChatGPT's most-cited domain (13.15% of citations), with Reddit close behind (11.97%) — Similarweb, Jan–Feb 2026.
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Citations are highly concentrated: roughly 30 domains capture about 67% of ChatGPT citations within a topic, and the top 10 capture around 46% (Search Engine Land / Kevin Indig, 2026).
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Authority wins: 65.3% of ChatGPT's top-cited pages come from domains with a Domain Rating of 81+ (Ahrefs, Sept 2025).
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Engines disagree: YouTube dominates Perplexity and Google AI Overviews but is largely absent from ChatGPT's top domains.
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Rankings are volatile: Reddit's citation share in ChatGPT swung from ~60% to ~10% of prompt responses in about six weeks in 2025 (Semrush) — any single ranking is a moment in time. For more context, see the broader 2026 AI search statistics.
What are the most-cited domains in ChatGPT?🔗
The clearest recent measurement of ChatGPT's most-cited domains comes from Similarweb, which analyzed about 600,000 ChatGPT citation events from US users in January–February 2026. The table below shows the top domains by share of ChatGPT citations.
Methodology: ~600,000 ChatGPT citation events, US, January–February 2026. Share = a domain's citations as a percentage of all citations in the sample. Source: Similarweb.
| Rank | Domain | Share of ChatGPT citations |
|---|---|---|
| 1 | wikipedia.org | 13.15% |
| 2 | reddit.com | 11.97% |
| 3 | openai.com | 6.21% |
| 4 | walmart.com | 2.90% |
| 5 | youtube.com | 2.67% |
| 6 | linkedin.com | 2.42% |
| 7 | reuters.com | 2.27% |
| 8 | nih.gov | 2.22% |
| 9 | google.com | 2.17% |
| 10 | media-amazon.com | 1.94% |
Other studies using different datasets and time windows land in the same neighborhood. Profound, analyzing 680 million citations from August 2024 to June 2025, found Wikipedia at 7.8% of all ChatGPT citations — and 47.9% of ChatGPT's top-10 sources. Ahrefs, across ~78.6 million searches in June 2025, put Wikipedia at 16.3% of ChatGPT citations. The exact percentage moves, but the leaders — Wikipedia, Reddit, major news, and high-authority reference sites — stay remarkably consistent.
Why does ChatGPT cite these domains?🔗
ChatGPT cites these domains because they combine three things AI engines reward: authority, structure, and being referenced everywhere else. Wikipedia and Reddit aren't cited because of clever SEO — they're cited because they are broad, frequently updated, heavily linked, and structurally easy to extract from.
The data backs this up. Ahrefs found that 65.3% of ChatGPT's top-1,000 cited pages come from domains with a Domain Rating of 81+, and 29.7% of those pages are Wikipedia. Search Engine Land's coverage of Kevin Indig's citation study found that pages ranking #1 in Google were cited by ChatGPT 43.2% of the time — 3.5x more often than pages beyond the top 20 — while 85% of retrieved pages received zero citations. In other words, ChatGPT concentrates its trust on a small set of authoritative, well-ranked sources.
How concentrated are ChatGPT citations?🔗
ChatGPT citations are extremely concentrated on a handful of domains. Per Search Engine Land / Kevin Indig (2026), within a given topic roughly 30 domains capture about 67% of citations, and the top 10 alone capture around 46%. That concentration is the single most important fact for anyone trying to earn AI citations: you're competing for a narrow set of slots dominated by high-authority sources.
This is also why "just publish more" rarely works. To break into ChatGPT's citations, content has to be authoritative and extractable enough to displace or sit alongside those incumbents — the mechanics we cover in how to get cited by ChatGPT and what sources ChatGPT cites.
Do other AI engines cite the same domains?🔗
No — the most-cited domains differ sharply by engine, which is why you can't optimize for "AI search" as one thing. According to Ahrefs (June 2025) and Profound:
- ChatGPT: Wikipedia leads; YouTube is notably absent from its top domains.
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Perplexity: Reddit and YouTube lead (YouTube ~16.1% in Ahrefs' data); Wikipedia is far less dominant.
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Google AI Overviews: YouTube (~9.5%), Reddit, and Quora lead; Wikipedia's share is small.
A separate SE Ranking study found the highest cross-engine domain overlap was just 25.19% (Perplexity vs. ChatGPT) and the lowest 9.81% (Bing vs. Google AI Overviews). The takeaway: winning in ChatGPT doesn't mean you're winning in Perplexity or Google AI Overviews. You have to measure each engine separately.
Important caveats about "most-cited domain" rankings🔗
Before you act on any ranking, understand its limits:
- Studies measure different things. Some report a domain's share of all citations (Similarweb, Profound), others report the share of prompt responses that include a domain (Semrush), which produces much larger numbers. Don't compare a "13%" from one study with a "55%" from another — they use different denominators.
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Rankings are volatile. Semrush documented ChatGPT's Reddit citation share falling from close to 60% of prompt responses in early August 2025 to around 10% by mid-September 2025 after a sourcing change. Any single snapshot captures one moment.
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It varies by query type. Health queries surface NIH and medical sites; gaming surfaces YouTube and Reddit; B2B software surfaces G2 and LinkedIn. There is no universal ranking that applies to your specific category.
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This is vendor data, not peer-reviewed research. These figures come from AI-visibility and SEO tools using proprietary methods and undisclosed query sets. They're directionally useful, not definitive.
What this means for your brand🔗
You almost certainly won't out-rank Wikipedia or Reddit — but you don't have to. The practical move is twofold: get your brand mentioned on the domains ChatGPT already trusts (earn a Reddit thread, a G2 profile, a news mention, a well-cited industry site), and make your own content authoritative and extractable so it can earn citations in your specific category, where concentration is lower than the global picture suggests.
The first step is knowing where you stand. TrendlyAI tracks which sources ChatGPT, Perplexity, and Google AI Overviews cite when people ask about your category, whether your brand is among them, and how you compare to competitors — so you can target the domains and content that actually move your AI visibility score. It's part of a broader generative engine optimization practice.
Frequently asked questions🔗
What is the most-cited domain in ChatGPT?🔗
Wikipedia is the most-cited domain in ChatGPT. Similarweb's analysis of ~600,000 US ChatGPT citations (January–February 2026) put Wikipedia at 13.15% of citations, ahead of Reddit at 11.97%. Multiple other studies from 2025–2026 also rank Wikipedia first for ChatGPT.
How many domains do most ChatGPT citations come from?🔗
ChatGPT citations are highly concentrated. Within a given topic, roughly 30 domains capture about 67% of citations, and the top 10 capture around 46%, according to Kevin Indig's 2026 study reported by Search Engine Land. That concentration makes AI citations a competitive, high-authority space.
Are the most-cited domains the same across ChatGPT, Perplexity, and Google?🔗
No. YouTube dominates Perplexity and Google AI Overviews but is largely absent from ChatGPT's top domains, where Wikipedia leads. Cross-engine domain overlap is low — as little as ~10–25% between engines — so you should measure each engine separately.
Can my brand get cited by ChatGPT?🔗
Yes, especially within your specific category, where citation concentration is lower than the global averages. The two most effective paths are earning mentions on high-authority domains ChatGPT already trusts (Reddit, news, review sites) and publishing authoritative, well-structured content of your own that AI engines can extract and cite.
Related reading🔗
Sources: Similarweb — Most Cited Domains by LLMs · Profound — AI Platform Citation Patterns · Ahrefs — Most Cited Domains in AI Assistants · Search Engine Land — ChatGPT citations study · Semrush — Most-Cited Domains in AI
Last updated: July 2026
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