diff --git a/report_builder/models.py b/report_builder/models.py
index e56aa4e5..116355f3 100644
--- a/report_builder/models.py
+++ b/report_builder/models.py
@@ -2,9 +2,10 @@
 from django.contrib.contenttypes.models import ContentType
 from django.conf import settings
 from django.core.urlresolvers import reverse
-from django.core.exceptions import ValidationError, ObjectDoesNotExist
+from django.core.exceptions import ValidationError, ObjectDoesNotExist, ImproperlyConfigured
 from django.utils.safestring import mark_safe
 from django.utils.functional import cached_property
+from django.utils.lru_cache import lru_cache
 from django.db import models
 from django.db.models import Avg, Min, Max, Count, Sum, F
 from django.db.models.fields import FieldDoesNotExist
@@ -21,30 +22,54 @@
 
 AUTH_USER_MODEL = getattr(settings, 'AUTH_USER_MODEL', 'auth.User')
 
+@lru_cache(maxsize=None)
+def get_model_contenttype(name):
+    if "." in name:
+        # Fully qualified model name
+        split_name = name.lower().split('.')
+        # Negative indexing allows, eg. "django.contrib.auth.User"
+        model_query = {
+                'app_label':split_name[-2], 
+                'model': split_name[-1]
+                }
+        model_name = "%s.%s" % (model_query['app_label'], model_query['model'])
+    else:
+        # short model name
+        model_query = {'model': name.lower()}
+        model_name = model_query['model']
+
+    # ensure it exists, and warn early if there's an issue
+    try:
+        model_ct = ContentType.objects.get(**model_query)
+    except ContentType.DoesNotExist:
+        raise ImproperlyConfigured(
+                "REPORT_BUILDER: Model '%s' (from '%s') could not be found." %
+                (model_name, name)
+                )
+    except ContentType.MultipleObjectsReturned:
+        possible_cts = ContentType.objects.filter(**model_query).values_list('app_label', 'model')
+        possible_cts = [".".join(ct) for ct in possible_cts]
+
+        raise ImproperlyConfigured(
+                "REPORT_BUILDER: Model '%s' is ambiguous. Possible values: %s" %
+                (name, str(possible_cts))
+                )
+    else:
+        return model_ct
 
 def get_allowed_models():
     models = ContentType.objects.all()
     if getattr(settings, 'REPORT_BUILDER_INCLUDE', False):
-        all_model_names = []
-        additional_models = []
+        ct_pks = [] # pks of all included model contenttypes
         for element in settings.REPORT_BUILDER_INCLUDE:
-            split_element = element.split('.')
-            if len(split_element) == 2:
-                additional_models.append(models.filter(app_label=split_element[0], model=split_element[1]))
-            else:
-                all_model_names.append(element)
-        models = models.filter(model__in=all_model_names)
-        for additional_model in additional_models:
-            models = models | additional_model
+            ct_pks.append(get_model_contenttype(element).pk)
+        models = ContentType.objects.filter(pk__in=ct_pks)
+
     if getattr(settings, 'REPORT_BUILDER_EXCLUDE', False):
-        all_model_names = []
+        ct_pks = [] # pks of all excluded model contenttypes
         for element in settings.REPORT_BUILDER_EXCLUDE:
-            split_element = element.split('.')
-            if len(split_element) == 2:
-                models = models.exclude(app_label=split_element[0], model=split_element[1])
-            else:
-                all_model_names.append(element)
-        models = models.exclude(model__in=all_model_names)
+            ct_pks.append(get_model_contenttype(element).pk)
+        models = models.exclude(pk__in=ct_pks)
     return models
 
 
diff --git a/report_builder/tests.py b/report_builder/tests.py
index 023e894e..ca59c200 100644
--- a/report_builder/tests.py
+++ b/report_builder/tests.py
@@ -1,6 +1,7 @@
 from django.contrib.contenttypes.models import ContentType
 from django.core import mail
 from django.core.urlresolvers import reverse
+from django.core.exceptions import ImproperlyConfigured
 from django.db.models.query import QuerySet
 from django.test import TestCase
 from django.test.utils import override_settings
@@ -155,6 +156,37 @@ def setUp(self):
         self.client = APIClient()
         self.client.login(username='testy', password='pass')
 
+    def test_bad_names(self):
+        settings.REPORT_BUILDER_EXCLUDE = None
+
+        # 'bar' is ambiguous
+        settings.REPORT_BUILDER_INCLUDE = ('bar',)
+        with self.assertRaises(ImproperlyConfigured):
+            get_allowed_models()
+
+        # app_label is invalid
+        settings.REPORT_BUILDER_INCLUDE = ('invalid.bar',)
+        with self.assertRaises(ImproperlyConfigured):
+            get_allowed_models()
+        settings.REPORT_BUILDER_INCLUDE = ('invalid.invalid',)
+        with self.assertRaises(ImproperlyConfigured):
+            get_allowed_models()
+
+        # model is invalid
+        settings.REPORT_BUILDER_INCLUDE = ('invalid',)
+        with self.assertRaises(ImproperlyConfigured):
+            get_allowed_models()
+        settings.REPORT_BUILDER_INCLUDE = ('demo_models.invalid',)
+        with self.assertRaises(ImproperlyConfigured):
+            get_allowed_models()
+
+        # ensure duplicate models don't overlap
+        settings.REPORT_BUILDER_INCLUDE = (
+            'demo_models.bar',
+            'demo_second_app.bar',
+        )
+        self.assertEqual(len(get_allowed_models()), 2)
+
     def test_get_allowed_models_for_include(self):
         pre_include_duplicates = find_duplicates_in_contexttype()
         settings.REPORT_BUILDER_INCLUDE = (