diff --git a/docs/configobj.rst b/docs/configobj.rst
index 17dcddf..391fd26 100644
--- a/docs/configobj.rst
+++ b/docs/configobj.rst
@@ -522,7 +522,7 @@ validate
 
 .. code-block:: python
 
-    validate(validator, preserve_errors=False, copy=False)
+    validate(validator, preserve_errors=False, copy=False, strict_spec=False)
 
 .. code-block:: python
 
diff --git a/src/configobj/__init__.py b/src/configobj/__init__.py
index 26239c6..d0430a9 100644
--- a/src/configobj/__init__.py
+++ b/src/configobj/__init__.py
@@ -2098,7 +2098,7 @@ def write(self, outfile=None, section=None):
                 h.write(output_bytes)
 
     def validate(self, validator, preserve_errors=False, copy=False,
-                 section=None):
+                 section=None, strict_spec=False):
         """
         Test the ConfigObj against a configspec.
 
@@ -2129,6 +2129,13 @@ def validate(self, validator, preserve_errors=False, copy=False,
 
         You must have the validate module to use ``preserve_errors=True``.
 
+        If ``strict_spec`` is ``True`` (``False`` is default) then instead of
+        ignoring entries undefined by the configspec, unrecognized entries will
+        fail validation and be inserted into the return dictionary with an
+        informational ``ValidateError``.
+
+        You must have the validate module to use ``strict_spec=True``.
+
         You can then use the ``flatten_errors`` function to turn your nested
         results dictionary into a flattened list of failures - useful for
         displaying meaningful error messages.
@@ -2139,7 +2146,8 @@ def validate(self, validator, preserve_errors=False, copy=False,
             if preserve_errors:
                 # We do this once to remove a top level dependency on the validate module
                 # Which makes importing configobj faster
-                from configobj.validate import VdtMissingValue
+                from configobj.validate import VdtMissingDefinition, VdtMissingValue
+                self._vdtMissingDefinition = VdtMissingDefinition
                 self._vdtMissingValue = VdtMissingValue
 
             section = self
@@ -2263,6 +2271,15 @@ def validate_entry(entry, spec, val, missing, ret_true, ret_false):
                 ret_false = False
                 msg = 'Section %r was provided as a single value' % entry
                 out[entry] = validator.baseErrorClass(msg)
+        if strict_spec:
+            for entry in unvalidated:
+                if not preserve_errors:
+                    out[entry] = False
+                else:
+                    ret_false = False
+                    msg = 'Value %r was unrecognized' % entry
+                    out[entry] = self._vdtMissingDefinition(msg)
+
 
         # Missing sections will have been created as empty ones when the
         # configspec was read.
diff --git a/src/configobj/validate.py b/src/configobj/validate.py
index b4873fb..25cb4fc 100644
--- a/src/configobj/validate.py
+++ b/src/configobj/validate.py
@@ -147,6 +147,7 @@
     'VdtValueTooBigError',
     'VdtValueTooShortError',
     'VdtValueTooLongError',
+    'VdtMissingDefinition',
     'VdtMissingValue',
     'Validator',
     'is_integer',
@@ -368,6 +369,10 @@ class ValidateError(Exception):
     """
 
 
+class VdtMissingDefinition(ValidateError):
+    """A check was requested on an undefined entry"""
+
+
 class VdtMissingValue(ValidateError):
     """No value was supplied to a check that needed one."""
 
diff --git a/src/tests/test_validate_errors.py b/src/tests/test_validate_errors.py
index b256efa..8fed86b 100644
--- a/src/tests/test_validate_errors.py
+++ b/src/tests/test_validate_errors.py
@@ -48,6 +48,11 @@ def test_validate_preserve_errors(conf):
     assert not section['missing-subsection']
 
 
+def test_validate_strict_spec(conf):
+    conf['undefined-entry'] = True
+    assert not conf.validate(Validator(), strict_spec=True)
+
+
 def test_validate_extra_values(conf):
     conf.validate(Validator(), preserve_errors=True)