diff --git a/superset/initialization/__init__.py b/superset/initialization/__init__.py
index 65f7977d4d2..7f79fbc3b0d 100644
--- a/superset/initialization/__init__.py
+++ b/superset/initialization/__init__.py
@@ -654,7 +654,24 @@ class SupersetAppInitializer:  # pylint: disable=too-many-public-methods
         logger.warning(bottom_banner)
 
     def check_secret_key(self) -> None:
-        if self.config["SECRET_KEY"] == CHANGE_ME_SECRET_KEY:
+        secret_key = self.config["SECRET_KEY"]
+        # A missing/empty SECRET_KEY is as insecure as the well-known default
+        # placeholder: both are treated as insecure and handled identically. An
+        # empty key is reachable when a deployment explicitly sets SECRET_KEY to
+        # an empty value (the env fallback only substitutes the placeholder).
+        if secret_key and secret_key != CHANGE_ME_SECRET_KEY:
+            return
+        if not secret_key:
+            warning = (
+                "An empty SECRET_KEY was detected, please use superset_config.py "
+                "to set a non-empty value.\n"
+                "Use a strong complex alphanumeric string and use a tool to help"
+                " you generate \n"
+                "a sufficiently random sequence, ex: openssl rand -base64 42 \n"
+                "For more info, see: https://superset.apache.org/docs/"
+                "configuration/configuring-superset#specifying-a-secret_key"
+            )
+        else:
             warning = (
                 "A Default SECRET_KEY was detected, please use superset_config.py "
                 "to override it.\n"
@@ -664,17 +681,13 @@ class SupersetAppInitializer:  # pylint: disable=too-many-public-methods
                 "For more info, see: https://superset.apache.org/docs/"
                 "configuration/configuring-superset#specifying-a-secret_key"
             )
-            if (
-                self.superset_app.debug
-                or self.superset_app.config["TESTING"]
-                or is_test()
-            ):
-                logger.warning("Debug mode identified with default secret key")
-                self._log_config_warning(warning)
-                return
+        if self.superset_app.debug or self.superset_app.config["TESTING"] or is_test():
+            logger.warning("Debug mode identified with insecure secret key")
             self._log_config_warning(warning)
-            logger.error("Refusing to start due to insecure SECRET_KEY")
-            sys.exit(1)
+            return
+        self._log_config_warning(warning)
+        logger.error("Refusing to start due to insecure SECRET_KEY")
+        sys.exit(1)
 
     def check_guest_token_secret(self) -> None:
         """Refuse to start with default guest JWT secret when embedding is enabled."""
diff --git a/tests/unit_tests/test_check_secret_key.py b/tests/unit_tests/test_check_secret_key.py
new file mode 100644
index 00000000000..e1416276925
--- /dev/null
+++ b/tests/unit_tests/test_check_secret_key.py
@@ -0,0 +1,74 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License 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.
+"""Tests for SupersetAppInitializer.check_secret_key."""
+
+from typing import Optional
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from superset.constants import CHANGE_ME_SECRET_KEY
+from superset.initialization import SupersetAppInitializer
+
+
+def _make_initializer(
+    secret_key: Optional[str],
+    *,
+    debug: bool = False,
+    testing: bool = False,
+) -> SupersetAppInitializer:
+    """Build a bare initializer with just the attributes check_secret_key needs."""
+    init = object.__new__(SupersetAppInitializer)
+    init.config = {"SECRET_KEY": secret_key}
+    app = MagicMock()
+    app.debug = debug
+    app.config = {"TESTING": testing}
+    init.superset_app = app
+    return init
+
+
+@pytest.mark.parametrize("secret_key", ["", None, CHANGE_ME_SECRET_KEY])
+def test_check_secret_key_refuses_to_start_when_insecure(
+    secret_key: Optional[str],
+) -> None:
+    """An empty/missing or placeholder key fails closed in non-debug mode."""
+    initializer = _make_initializer(secret_key)
+    with patch("superset.initialization.is_test", return_value=False):
+        with pytest.raises(SystemExit):
+            initializer.check_secret_key()
+
+
+@pytest.mark.parametrize("secret_key", ["", None, CHANGE_ME_SECRET_KEY])
+def test_check_secret_key_warns_but_starts_in_debug(
+    secret_key: Optional[str],
+) -> None:
+    """In debug/testing mode an insecure key warns but does not exit."""
+    initializer = _make_initializer(secret_key, debug=True)
+    with patch("superset.initialization.is_test", return_value=False):
+        # Should not raise SystemExit.
+        initializer.check_secret_key()
+
+
+def test_check_secret_key_accepts_strong_key() -> None:
+    """A non-empty, non-placeholder key starts without warning or exit."""
+    initializer = _make_initializer("a-strong-random-secret-key")
+    with (
+        patch("superset.initialization.is_test", return_value=False),
+        patch.object(initializer, "_log_config_warning") as log_warning,
+    ):
+        initializer.check_secret_key()
+    log_warning.assert_not_called()