diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..70c9039
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 PolicyEngine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
index 9c2f2e9..201f798 100644
--- a/README.md
+++ b/README.md
@@ -42,3 +42,7 @@ pip install microimpute[images]
 ## Contributing
 
 Pull requests are welcome. If you find a bug or have a feature idea, open an issue or submit a PR.
+
+## License
+
+Code in this repository is released under the [MIT License](LICENSE). Original text and figures are released under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) with attribution to PolicyEngine. Third-party data and materials keep their own terms.