diff --git a/thirdparty/README.md b/thirdparty/README.md
index 2c3c037f3a7..2aac8c73aa8 100644
--- a/thirdparty/README.md
+++ b/thirdparty/README.md
@@ -41,3 +41,7 @@ CMake instructions to build [Pybind11](https://github.com/pybind/pybind11), whic
 ## FRNN
 
 CMake instructions to build [FRNN](https://github.com/lxxue/FRNN), which is used by the Exa.TrkX plugin.
+
+## Annoy
+
+CMake instructions to build [Annoy](https://github.com/spotify/annoy) which is used by the Hashing plugin.