diff --git a/sagemaker-mlops/src/sagemaker/__init__.py b/sagemaker-mlops/src/sagemaker/__init__.py
deleted file mode 100644
index 33b1b0d2b8..0000000000
--- a/sagemaker-mlops/src/sagemaker/__init__.py
+++ /dev/null
@@ -1,3 +0,0 @@
-"""Namespace package for SageMaker."""
-
-__path__ = __import__("pkgutil").extend_path(__path__, __name__)
diff --git a/sagemaker-mlops/tests/unit/test_namespace_packaging.py b/sagemaker-mlops/tests/unit/test_namespace_packaging.py
new file mode 100644
index 0000000000..6e6cfe1a6e
--- /dev/null
+++ b/sagemaker-mlops/tests/unit/test_namespace_packaging.py
@@ -0,0 +1,38 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+"""Regression guard for GH #5795.
+
+sagemaker-mlops must not ship its own top-level ``sagemaker/__init__.py``:
+sagemaker-core owns that file, and having two distributions install the same
+path makes strict installers / OS package managers refuse to co-install them.
+The ``sagemaker`` package is a namespace shared across the sub-distributions.
+"""
+
+from __future__ import absolute_import
+
+from pathlib import Path
+
+_SRC = Path(__file__).resolve().parents[2] / "src"
+
+
+def test_does_not_ship_top_level_sagemaker_init():
+    top_level_init = _SRC / "sagemaker" / "__init__.py"
+    assert not top_level_init.exists(), (
+        f"{top_level_init} must not exist: sagemaker-core owns "
+        "sagemaker/__init__.py (see GH #5795)."
+    )
+
+
+def test_still_ships_the_subpackage_init():
+    # The distribution's own sub-package must remain a real package.
+    assert (_SRC / "sagemaker" / "mlops" / "__init__.py").exists()
diff --git a/sagemaker-mlops/tox.ini b/sagemaker-mlops/tox.ini
index df0cde820c..a1b3d0a6f9 100644
--- a/sagemaker-mlops/tox.ini
+++ b/sagemaker-mlops/tox.ini
@@ -136,7 +136,7 @@ setenv =
 deps =
     -r ../requirements/tox/pylint_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc -j 0 src/sagemaker --fail-under=9.9
+    python -m pylint --rcfile=../.pylintrc -j 0 --recursive=y src/sagemaker --fail-under=9.9
 
 [testenv:spelling]
 skipdist = true
@@ -144,7 +144,7 @@ skip_install = true
 deps =
     -r ../requirements/tox/spelling_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US src/sagemaker/{posargs}
+    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US --recursive=y src/sagemaker/{posargs}
 
 [testenv:twine]
 # https://packaging.python.org/guides/making-a-pypi-friendly-readme/#validating-restructuredtext-markup
diff --git a/sagemaker-serve/src/sagemaker/__init__.py b/sagemaker-serve/src/sagemaker/__init__.py
deleted file mode 100644
index 33b1b0d2b8..0000000000
--- a/sagemaker-serve/src/sagemaker/__init__.py
+++ /dev/null
@@ -1,3 +0,0 @@
-"""Namespace package for SageMaker."""
-
-__path__ = __import__("pkgutil").extend_path(__path__, __name__)
diff --git a/sagemaker-serve/tests/unit/test_namespace_packaging.py b/sagemaker-serve/tests/unit/test_namespace_packaging.py
new file mode 100644
index 0000000000..e23914301d
--- /dev/null
+++ b/sagemaker-serve/tests/unit/test_namespace_packaging.py
@@ -0,0 +1,38 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+"""Regression guard for GH #5795.
+
+sagemaker-serve must not ship its own top-level ``sagemaker/__init__.py``:
+sagemaker-core owns that file, and having two distributions install the same
+path makes strict installers / OS package managers refuse to co-install them.
+The ``sagemaker`` package is a namespace shared across the sub-distributions.
+"""
+
+from __future__ import absolute_import
+
+from pathlib import Path
+
+_SRC = Path(__file__).resolve().parents[2] / "src"
+
+
+def test_does_not_ship_top_level_sagemaker_init():
+    top_level_init = _SRC / "sagemaker" / "__init__.py"
+    assert not top_level_init.exists(), (
+        f"{top_level_init} must not exist: sagemaker-core owns "
+        "sagemaker/__init__.py (see GH #5795)."
+    )
+
+
+def test_still_ships_the_subpackage_init():
+    # The distribution's own sub-package must remain a real package.
+    assert (_SRC / "sagemaker" / "serve" / "__init__.py").exists()
diff --git a/sagemaker-serve/tox.ini b/sagemaker-serve/tox.ini
index 1cfab1a3e9..09837c7d7e 100644
--- a/sagemaker-serve/tox.ini
+++ b/sagemaker-serve/tox.ini
@@ -138,7 +138,7 @@ setenv =
 deps =
     -r ../requirements/tox/pylint_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc -j 0 src/sagemaker --fail-under=9.9
+    python -m pylint --rcfile=../.pylintrc -j 0 --recursive=y src/sagemaker --fail-under=9.9
 
 [testenv:spelling]
 skipdist = true
@@ -146,7 +146,7 @@ skip_install = true
 deps =
     -r ../requirements/tox/spelling_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US src/sagemaker/{posargs}
+    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US --recursive=y src/sagemaker/{posargs}
 
 [testenv:twine]
 # https://packaging.python.org/guides/making-a-pypi-friendly-readme/#validating-restructuredtext-markup
diff --git a/sagemaker-train/src/sagemaker/__init__.py b/sagemaker-train/src/sagemaker/__init__.py
deleted file mode 100644
index 33b1b0d2b8..0000000000
--- a/sagemaker-train/src/sagemaker/__init__.py
+++ /dev/null
@@ -1,3 +0,0 @@
-"""Namespace package for SageMaker."""
-
-__path__ = __import__("pkgutil").extend_path(__path__, __name__)
diff --git a/sagemaker-train/tests/unit/test_namespace_packaging.py b/sagemaker-train/tests/unit/test_namespace_packaging.py
new file mode 100644
index 0000000000..f3c96d8ea2
--- /dev/null
+++ b/sagemaker-train/tests/unit/test_namespace_packaging.py
@@ -0,0 +1,38 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+"""Regression guard for GH #5795.
+
+sagemaker-train must not ship its own top-level ``sagemaker/__init__.py``:
+sagemaker-core owns that file, and having two distributions install the same
+path makes strict installers / OS package managers refuse to co-install them.
+The ``sagemaker`` package is a namespace shared across the sub-distributions.
+"""
+
+from __future__ import absolute_import
+
+from pathlib import Path
+
+_SRC = Path(__file__).resolve().parents[2] / "src"
+
+
+def test_does_not_ship_top_level_sagemaker_init():
+    top_level_init = _SRC / "sagemaker" / "__init__.py"
+    assert not top_level_init.exists(), (
+        f"{top_level_init} must not exist: sagemaker-core owns "
+        "sagemaker/__init__.py (see GH #5795)."
+    )
+
+
+def test_still_ships_the_subpackage_init():
+    # The distribution's own sub-package must remain a real package.
+    assert (_SRC / "sagemaker" / "train" / "__init__.py").exists()
diff --git a/sagemaker-train/tox.ini b/sagemaker-train/tox.ini
index b083a374e1..2b631d0bff 100644
--- a/sagemaker-train/tox.ini
+++ b/sagemaker-train/tox.ini
@@ -143,7 +143,7 @@ setenv =
 deps =
     -r ../requirements/tox/pylint_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc -j 0 src/sagemaker --fail-under=9.9
+    python -m pylint --rcfile=../.pylintrc -j 0 --recursive=y src/sagemaker --fail-under=9.9
 
 [testenv:spelling]
 skipdist = true
@@ -151,7 +151,7 @@ skip_install = true
 deps =
     -r ../requirements/tox/spelling_requirements.txt
 commands =
-    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US src/sagemaker/{posargs}
+    python -m pylint --rcfile=../.pylintrc --disable all --enable spelling --spelling-dict en_US --recursive=y src/sagemaker/{posargs}
 
 [testenv:twine]
 # https://packaging.python.org/guides/making-a-pypi-friendly-readme/#validating-restructuredtext-markup