diff --git a/noxfile.py b/noxfile.py
index cc6c05ef..ecef4b1a 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -118,7 +118,7 @@ def pypy_setup(local_deps, session):
         # Install NumPy and SciPy from pre-built wheels. Don't use ``DEPS``
         # to specify version range for NumPy and SciPy.
         session.install(
-            "--no-index", "--find-links", wheelhouse, "numpy", "scipy"
+            "--no-index", "--find-links", str(wheelhouse), "numpy", "scipy"
         )
     return local_deps
 
@@ -184,7 +184,11 @@ def unit(session):
     # Install this package.
     install_bezier(session, debug=True)
     # Run pytest against the unit tests.
-    run_args = ["pytest"] + session.posargs + [get_path("tests", "unit")]
+    run_args = (
+        ["python", "-m", "pytest"]
+        + session.posargs
+        + [get_path("tests", "unit")]
+    )
     session.run(*run_args)
 
 
@@ -201,7 +205,7 @@ def cover(session):
     # Install this package.
     install_bezier(session, debug=True)
     # Run pytest with coverage against the unit tests.
-    run_args = ["pytest", "--cov=bezier", "--cov=tests.unit"]
+    run_args = ["python", "-m", "pytest", "--cov=bezier", "--cov=tests.unit"]
     run_args += session.posargs
     run_args += [get_path("tests", "unit")]
     session.run(*run_args)
@@ -220,7 +224,11 @@ def functional(session):
     # Install this package.
     install_bezier(session, debug=True)
     # Run pytest against the functional tests.
-    run_args = ["pytest"] + session.posargs + [get_path("tests", "functional")]
+    run_args = (
+        ["python", "-m", "pytest"]
+        + session.posargs
+        + [get_path("tests", "functional")]
+    )
     session.run(*run_args)
 
 
diff --git a/setup.py b/setup.py
index a818d582..37f4611e 100644
--- a/setup.py
+++ b/setup.py
@@ -21,6 +21,7 @@
 import pkg_resources
 import setuptools
 import setuptools.command.build_ext
+import setuptools.dist
 
 
 VERSION = "2021.2.13.dev1"  # Also in ``codemeta.json`` and ``__init__.py``.
@@ -71,6 +72,7 @@
     "Helper for B\u00e9zier Curves, Triangles, and Higher Order Objects"
 )
 _IS_WINDOWS = os.name == "nt"
+_IS_PYPY = sys.implementation.name == "pypy"
 _EXTRA_DLL = "extra-dll"
 _DLL_FILENAME = "bezier.dll"
 
@@ -267,7 +269,24 @@ def setup():
     )
 
 
+def _patch_setuptools():
+    """Patch ``setuptools`` to address known issues.
+
+    Known issues:
+    * In some PyPy installs, the ``setuptools.build_py.build_package_data()``
+      method depends on the ``convert_2to3_doctests`` being set on an instance
+      of ``setuptools.dist.Distribution``, but it is unset. We handle this
+      by setting it as a **class attribute** (vs. monkey-patching ``__init__``
+      to set it on instances).
+    """
+    if not _IS_PYPY:
+        return
+
+    setuptools.dist.Distribution.convert_2to3_doctests = []
+
+
 def main():
+    _patch_setuptools()
     setup()