diff --git a/setup.cfg b/setup.cfg
index 75d628a6..4bbb137a 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -25,10 +25,15 @@ classifiers =
     Programming Language :: Python :: 3.10
 
 [options]
+package_dir=
+    = src
 packages = typeguard
 python_requires = >= 3.5.3
 zip_safe = False
 
+[options.packages.find]
+where = src
+
 [options.package_data]
 typeguard = py.typed
 
diff --git a/typeguard/__init__.py b/src/typeguard/__init__.py
similarity index 100%
rename from typeguard/__init__.py
rename to src/typeguard/__init__.py
diff --git a/typeguard/importhook.py b/src/typeguard/importhook.py
similarity index 100%
rename from typeguard/importhook.py
rename to src/typeguard/importhook.py
diff --git a/typeguard/py.typed b/src/typeguard/py.typed
similarity index 100%
rename from typeguard/py.typed
rename to src/typeguard/py.typed
diff --git a/typeguard/pytest_plugin.py b/src/typeguard/pytest_plugin.py
similarity index 100%
rename from typeguard/pytest_plugin.py
rename to src/typeguard/pytest_plugin.py
diff --git a/tox.ini b/tox.ini
index 6e2f3a58..999ef4ce 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,5 +14,5 @@ commands =
 
 [testenv:flake8]
 deps = flake8
-commands = flake8 typeguard tests
+commands = flake8 src tests
 skip_install = true