No. The top-level domain is .uk. .co.uk sits under .uk: Nominet registers .uk names at the second level, while example.co.uk is registered within the .co second-level domain, so .co.uk is effectively a third-level registration under the .uk TLD. (Nominet, 2018.)
Consumer help · Updated 4 June 2026
Is .co.uk a top-level domain?
How Nominet structures the .UK namespace
Nominet's Rules of Registration (2018) define .uk as the country-code top-level domain. Registrations such as example.uk sit at the second level. A name such as example.co.uk is registered within the .co second-level domain, which makes .co.uk effectively a third-level name under .uk, not a separate TLD.
What is the .uk domain, and what is the .ltd.uk domain?
.uk is the UK's country-code TLD, managed by Nominet. Beneath it sit second-level domains: .co.uk (commercial), .org.uk (organisations), .me.uk (individuals), .ltd.uk and .plc.uk (registered companies), .net.uk, plus restricted ones like .ac.uk, .gov.uk and .sch.uk. .ltd.uk is reserved for UK limited companies whose registered name matches. (Nominet, 2018.)
Second-level domains carry different eligibility rules; check Nominet policy for restricted suffixes.
Sources
- Nominet. (2018). Rules of registration.
- Nominet. (2025). UK registry.