Yes — but the combined work must be released under the more restrictive license.
The Unlicense code can be combined with GNU GPL v3.0 or later code without conflict. The combined work, when distributed, must be licensed under GNU GPL v3.0 or later. The original The Unlicense files keep their notice, but the project as a whole is governed by the stronger copyleft.
| License | Family | Patent grant |
|---|---|---|
| The Unlicense (Unlicense) | permissive | No (implicit at most) |
| GNU GPL v3.0 or later (GPL-3.0-or-later) | strong-copyleft | Yes |
The Unlicense: Public-domain dedication with a fallback license for jurisdictions that don't recognise PD.
GNU GPL v3.0 or later: GPL-3.0 with explicit upgrade path; users may pick GPL-3.0 or any later GPL.
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.