Yes — but the combined work must be released under the more restrictive license.
GNU Lesser GPL v3.0 is a file-level (or library-level) copyleft license. You can include GNU Lesser GPL v3.0 files in a The Unlicense project; the GNU Lesser GPL v3.0 files retain their copyleft obligation (changes must be released), while the project at large can stay The Unlicense. Keep file boundaries clear.
| License | Family | Patent grant |
|---|---|---|
| GNU Lesser GPL v3.0 (LGPL-3.0) | weak-copyleft | Yes |
| The Unlicense (Unlicense) | permissive | No (implicit at most) |
GNU Lesser GPL v3.0: Same library-linking permission as LGPL-2.1, with GPLv3's patent provisions inherited.
The Unlicense: Public-domain dedication with a fallback license for jurisdictions that don't recognise PD.
If you found this page because you're trying to figure out whether shipping a particular dependency is safe, the answer above is a starting point — not a substitute for reading the actual licenses or talking to a lawyer when stakes are high.
LicenseHound walks every transitive dependency in your repo, maps each to its SPDX license, and flags pairs like this one in PR comments. The CLI is free; the team dashboard is paid.