diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 97b2bedd..0dcd29cf 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -22,6 +22,7 @@ jobs:
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v2
     - uses: pre-commit/action@v2.0.3
+    - run: pipx run nox -s check_manifest
 
   test:
     name: Test cibuildwheel on ${{ matrix.os }}
diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 00000000..6fc0b394
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1,6 @@
+recursive-include cibuildwheel *.cfg
+recursive-include cibuildwheel *.in
+recursive-include cibuildwheel *.py
+recursive-include cibuildwheel *.toml
+recursive-include cibuildwheel *.txt
+recursive-include cibuildwheel *.typed
diff --git a/noxfile.py b/noxfile.py
index 0d4881e5..4ee397c9 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -4,7 +4,7 @@ from pathlib import Path
 
 import nox
 
-nox.options.sessions = ["lint", "tests"]
+nox.options.sessions = ["lint", "check_manifest", "tests"]
 
 PYTHON_ALL_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
 
@@ -34,6 +34,16 @@ def lint(session: nox.Session) -> None:
     session.run("pre-commit", "run", "--all-files", *session.posargs)
 
 
+@nox.session
+def check_manifest(session: nox.Session) -> None:
+    """
+    Ensure all needed files are included in the manifest.
+    """
+
+    session.install("check-manifest")
+    session.run("check-manifest", *session.posargs)
+
+
 @nox.session(python=PYTHON_ALL_VERSIONS)
 def update_constraints(session: nox.Session) -> None:
     """
diff --git a/pyproject.toml b/pyproject.toml
index 2789fd27..7a7aa8f3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -67,3 +67,18 @@ ignore_missing_imports = true
 
 [tool.pycln]
 all = true
+
+[tool.check-manifest]
+ignore = [
+    ".*",
+    ".circleci/**",
+    "test/**",
+    "unit_test/**",
+    "docs/**",
+    "examples/**",
+    "bin/**",
+    "*.yml",
+    "CI.md",  # TODO: can change test/test_ssl and remove this
+    "requirements-dev.txt",
+    "noxfile.py",
+]