diff --git a/pyproject.toml b/pyproject.toml
index 1e50c697ce..50aaf53b31 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -32,6 +32,9 @@ classifiers = [
     "Environment :: WebAssembly :: Emscripten",
     "Intended Audience :: Science/Research",
     "License :: OSI Approved :: Apache Software License",
+    "Operating System :: Microsoft :: Windows",
+    "Operating System :: MacOS",
+    "Operating System :: POSIX :: Linux",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.8",