diff --git a/pip/_vendor/pep517/in_process/__init__.py b/pip/_vendor/pep517/in_process/__init__.py
index 281a356cfe26..77acbfc2670b 100644
--- a/pip/_vendor/pep517/in_process/__init__.py
+++ b/pip/_vendor/pep517/in_process/__init__.py
@@ -14,13 +14,21 @@ try:
     except AttributeError:
         # Python 3.8 compatibility
         def _in_proc_script_path():
-            return resources.path(__package__, '_in_process.py')
+            if resources.is_resource(__package__, '_in_process.py'):
+                return resources.path(__package__, '_in_process.py')
+            return resources.path(__package__, '_in_process.pyc')
     else:
         def _in_proc_script_path():
+            if resources.files(__package__).joinpath('_in_process.py').is_file():
+                return resources.as_file(
+                    resources.files(__package__).joinpath('_in_process.py'))
             return resources.as_file(
-                resources.files(__package__).joinpath('_in_process.py'))
+                resources.files(__package__).joinpath('_in_process.pyc'))
 except ImportError:
     # Python 3.6 compatibility
     @contextmanager
     def _in_proc_script_path():
-        yield pjoin(dirname(abspath(__file__)), '_in_process.py')
+        _in_proc_script = pjoin(dirname(abspath(__file__)), '_in_process.py')
+        if not os.path.isfile(_in_proc_script):
+            _in_proc_script = pjoin(dirname(abspath(__file__)), '_in_process.pyc')
+        yield _in_proc_script