diff --git a/MANIFEST.in b/MANIFEST.in
index ba0fd4c..39c5b78 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,6 +2,7 @@ include *.py
 include CHANGELOG.md
 include LICENSE
 include README.md
+include tox.ini
 recursive-include tests *py
 recursive-include docs *.md
 include docs/conf.py
diff --git a/pyproject.toml b/pyproject.toml
index 7534da9..1355192 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,6 +36,7 @@ include = [
     { path = "docs/**/*.md", format = "sdist" },
     { path = "LICENSE", format = "sdist" },
     { path = "README.md", format = "sdist" },
+    { path = "tox.ini", format = "sdist" },
     { path = "tests/**/*.py", format = "sdist" },
     { path = "docs/conf.py", format = "sdist" },
     { path = "docs/toctree.rst", format = "sdist" },