diff --git a/mypy/parse.py b/mypy/parse.py
index f440be5d3d85..cc1b9153f5dd 100644
--- a/mypy/parse.py
+++ b/mypy/parse.py
@@ -32,12 +32,14 @@ def parse(
     parse contents from path `fnam` if `source` is `None`.
     """
     if options.native_parser:
-        import mypy.nativeparse
+        # Use import from as workaround for cpython#149728 - accessing mypy.nativeparse
+        # after importing it may fail when this function is called concurrently.
+        from mypy import nativeparse
 
         ignore_errors = options.ignore_errors or fnam in errors.ignored_files
         # If errors are ignored, we can drop many function bodies to speed up type checking.
         strip_function_bodies = ignore_errors and not options.preserve_asts
-        tree, _, _ = mypy.nativeparse.native_parse(
+        tree, _, _ = nativeparse.native_parse(
             fnam, options, source, skip_function_bodies=strip_function_bodies
         )
         # Set is_stub based on file extension
@@ -120,9 +122,11 @@ def report_parse_error(error: ParseError, errors: Errors) -> None:
 
 def parse_type_string(expr: StrExpr, options: Options) -> ProperType:
     if options.native_parser:
-        import mypy.nativeparse
+        # Use a import from as workaround for cpython#149728 - accessing mypy.nativeparse
+        # after importing it may fail when this function is called concurrently.
+        from mypy import nativeparse
 
-        return mypy.nativeparse.native_parse_type_string(
+        return nativeparse.native_parse_type_string(
             expr.value,
             expr.line,
             expr.column,
diff --git a/mypy/test/testcmdline.py b/mypy/test/testcmdline.py
index b558127d31dc..ced443e94f3d 100644
--- a/mypy/test/testcmdline.py
+++ b/mypy/test/testcmdline.py
@@ -13,7 +13,8 @@
 import sys
 import sysconfig
 
-from mypy.test.config import PREFIX, test_temp_dir
+import mypy
+from mypy.test.config import test_temp_dir
 from mypy.test.data import DataDrivenTestCase, DataSuite
 from mypy.test.helpers import (
     assert_string_arrays_equal,
@@ -72,7 +73,8 @@ def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
     env = os.environ.copy()
     env.pop("COLUMNS", None)
     extra_path = os.path.join(os.path.abspath(test_temp_dir), "pypath")
-    env["PYTHONPATH"] = PREFIX
+    # Use the same mypy installation as pytest, including the compiled wheel in CI.
+    env["PYTHONPATH"] = os.path.dirname(os.path.abspath(mypy.__path__[0]))
     if os.path.isdir(extra_path):
         env["PYTHONPATH"] += os.pathsep + extra_path
     cwd = os.path.join(test_temp_dir, custom_cwd or "")