diff --git a/scripts/mbedtls_dev/__init__.py b/scripts/mbedtls_dev/__init__.py
new file mode 100644
index 0000000000..c5bddaf74b
--- /dev/null
+++ b/scripts/mbedtls_dev/__init__.py
@@ -0,0 +1,3 @@
+# This file needs to exist to make mbedtls_dev a package.
+# Among other things, this allows modules in this directory to make
+# relative impotrs.
diff --git a/scripts/mbedtls_dev/crypto_knowledge.py b/scripts/mbedtls_dev/crypto_knowledge.py
index 592fc0afe2..1ce549903a 100644
--- a/scripts/mbedtls_dev/crypto_knowledge.py
+++ b/scripts/mbedtls_dev/crypto_knowledge.py
@@ -22,7 +22,7 @@ import enum
 import re
 from typing import FrozenSet, Iterable, List, Optional, Tuple
 
-from mbedtls_dev.asymmetric_key_data import ASYMMETRIC_KEY_DATA
+from .asymmetric_key_data import ASYMMETRIC_KEY_DATA
 
 
 def short_expression(original: str, level: int = 0) -> str:
diff --git a/scripts/mbedtls_dev/psa_storage.py b/scripts/mbedtls_dev/psa_storage.py
index a06dce13ba..bae99383dc 100644
--- a/scripts/mbedtls_dev/psa_storage.py
+++ b/scripts/mbedtls_dev/psa_storage.py
@@ -26,7 +26,7 @@ import struct
 from typing import Dict, List, Optional, Set, Union
 import unittest
 
-from mbedtls_dev import c_build_helper
+from . import c_build_helper
 
 
 class Expr:
diff --git a/scripts/mbedtls_dev/test_case.py b/scripts/mbedtls_dev/test_case.py
index d8f7b60040..43ddf203b6 100644
--- a/scripts/mbedtls_dev/test_case.py
+++ b/scripts/mbedtls_dev/test_case.py
@@ -21,7 +21,7 @@ import os
 import sys
 from typing import Iterable, List, Optional
 
-from mbedtls_dev import typing_util
+from . import typing_util
 
 def hex_string(data: bytes) -> str:
     return '"' + binascii.hexlify(data).decode('ascii') + '"'
diff --git a/scripts/mbedtls_dev/test_data_generation.py b/scripts/mbedtls_dev/test_data_generation.py
index 36c9475056..cdb1c03b89 100644
--- a/scripts/mbedtls_dev/test_data_generation.py
+++ b/scripts/mbedtls_dev/test_data_generation.py
@@ -29,8 +29,8 @@ import re
 from abc import ABCMeta, abstractmethod
 from typing import Callable, Dict, Iterable, Iterator, List, Type, TypeVar
 
-from mbedtls_dev import build_tree
-from mbedtls_dev import test_case
+from . import build_tree
+from . import test_case
 
 T = TypeVar('T') #pylint: disable=invalid-name