diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index 9e4b0a4b1e..6813afb3b8 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -115,15 +115,15 @@ class Settings:
             if setting.isupper():
                 setting_value = getattr(mod, setting)
 
+                if setting == 'SECRET_KEY' and not setting_value:
+                    raise ImproperlyConfigured('The SECRET_KEY setting must not be empty.')
+
                 if (setting in tuple_settings and
                         not isinstance(setting_value, (list, tuple))):
                     raise ImproperlyConfigured("The %s setting must be a list or a tuple. " % setting)
                 setattr(self, setting, setting_value)
                 self._explicit_settings.add(setting)
 
-        if not self.SECRET_KEY:
-            raise ImproperlyConfigured("The SECRET_KEY setting must not be empty.")
-
         if self.is_overridden('DEFAULT_CONTENT_TYPE'):
             warnings.warn('The DEFAULT_CONTENT_TYPE setting is deprecated.', RemovedInDjango30Warning)
 
@@ -139,6 +139,11 @@ class Settings:
             os.environ['TZ'] = self.TIME_ZONE
             time.tzset()
 
+    def __getattr__(self, name):
+        if name == 'SECRET_KEY':
+            raise ImproperlyConfigured('The SECRET_KEY setting must be set.')
+        raise AttributeError("'%s' object has no attribute '%s'" % (self.__class__.__name__, name))
+
     def is_overridden(self, setting):
         return setting in self._explicit_settings
 
diff --git a/django/conf/global_settings.py b/django/conf/global_settings.py
index befade160f..26fa492892 100644
--- a/django/conf/global_settings.py
+++ b/django/conf/global_settings.py
@@ -256,11 +256,6 @@ ABSOLUTE_URL_OVERRIDES = {}
 #    ]
 IGNORABLE_404_URLS = []
 
-# A secret key for this particular Django installation. Used in secret-key
-# hashing algorithms. Set this in your settings, or Django will complain
-# loudly.
-SECRET_KEY = ''
-
 # Default file storage mechanism that holds media.
 DEFAULT_FILE_STORAGE = 'django.core.files.storage.FileSystemStorage'
 
diff --git a/docs/ref/settings.txt b/docs/ref/settings.txt
index 3647e60663..635cadc848 100644
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
@@ -2074,7 +2074,7 @@ object. See :ref:`how-django-processes-a-request` for details.
 ``SECRET_KEY``
 --------------
 
-Default: ``''`` (Empty string)
+Default: Not defined
 
 A secret key for a particular Django installation. This is used to provide
 :doc:`cryptographic signing </topics/signing>`, and should be set to a unique,
@@ -2087,7 +2087,9 @@ Uses of the key shouldn't assume that it's text or bytes. Every use should go
 through :func:`~django.utils.encoding.force_text` or
 :func:`~django.utils.encoding.force_bytes` to convert it to the desired type.
 
-Django will refuse to start if :setting:`SECRET_KEY` is not set.
+Django will refuse to start if :setting:`SECRET_KEY` is set to an empty value.
+:class:`~django.core.exceptions.ImproperlyConfigured` is raised if
+``SECRET_KEY`` is accessed but not set.
 
 .. warning::
 
@@ -2120,6 +2122,10 @@ affect them.
     startproject <startproject>` creates a unique ``SECRET_KEY`` for
     convenience.
 
+.. versionchanged:: 2.1
+
+    In older versions, ``SECRET_KEY`` defaults to an empty string.
+
 .. setting:: SECURE_BROWSER_XSS_FILTER
 
 ``SECURE_BROWSER_XSS_FILTER``
diff --git a/tests/admin_scripts/tests.py b/tests/admin_scripts/tests.py
index 3c4e01dfac..17347a476b 100644
--- a/tests/admin_scripts/tests.py
+++ b/tests/admin_scripts/tests.py
@@ -2213,7 +2213,11 @@ class DiffSettings(AdminScriptTestCase):
         out, err = self.run_manage(args)
         self.assertNoOutput(err)
         self.assertOutput(out, "+ FOO = 'bar'")
-        self.assertOutput(out, "- SECRET_KEY = ''")
+        self.assertOutput(out, "- INSTALLED_APPS = []")
+        self.assertOutput(
+            out,
+            "+ INSTALLED_APPS = ['django.contrib.auth', 'django.contrib.contenttypes', 'admin_scripts']"
+        )
         self.assertOutput(out, "+ SECRET_KEY = 'django_tests_secret_key'")
         self.assertNotInOutput(out, "  APPEND_SLASH = True")
 
@@ -2229,7 +2233,12 @@ class DiffSettings(AdminScriptTestCase):
         self.assertNoOutput(err)
         self.assertOutput(out, "  APPEND_SLASH = True")
         self.assertOutput(out, "+ FOO = 'bar'")
-        self.assertOutput(out, "- SECRET_KEY = ''")
+        self.assertOutput(out, "- INSTALLED_APPS = []")
+        self.assertOutput(
+            out,
+            "+ INSTALLED_APPS = ['django.contrib.auth', 'django.contrib.contenttypes', 'admin_scripts']"
+        )
+        self.assertOutput(out, "+ SECRET_KEY = 'django_tests_secret_key'")
 
 
 class Dumpdata(AdminScriptTestCase):
diff --git a/tests/settings_tests/tests.py b/tests/settings_tests/tests.py
index 09c062c897..9187f87388 100644
--- a/tests/settings_tests/tests.py
+++ b/tests/settings_tests/tests.py
@@ -292,8 +292,20 @@ class SettingsTests(SimpleTestCase):
     def test_no_secret_key(self):
         settings_module = ModuleType('fake_settings_module')
         sys.modules['fake_settings_module'] = settings_module
-        msg = 'The SECRET_KEY setting must not be empty.'
+        msg = 'The SECRET_KEY setting must be set.'
         try:
+            settings = Settings('fake_settings_module')
+            with self.assertRaisesMessage(ImproperlyConfigured, msg):
+                settings.SECRET_KEY
+        finally:
+            del sys.modules['fake_settings_module']
+
+    def test_secret_key_empty_string(self):
+        settings_module = ModuleType('fake_settings_module')
+        settings_module.SECRET_KEY = ''
+        sys.modules['fake_settings_module'] = settings_module
+        try:
+            msg = 'The SECRET_KEY setting must not be empty.'
             with self.assertRaisesMessage(ImproperlyConfigured, msg):
                 Settings('fake_settings_module')
         finally: