diff --git a/readthedocs/projects/version_handling.py b/readthedocs/projects/version_handling.py
index 7a730e61fd0..15cfe8be91e 100644
--- a/readthedocs/projects/version_handling.py
+++ b/readthedocs/projects/version_handling.py
@@ -16,7 +16,9 @@ def parse_version_failsafe(version_string):
     """
     Parse a version in string form and return Version object.
 
-    If there is an error parsing the string, ``None`` is returned.
+    If there is an error parsing the string
+    or the version doesn't have a "comparable" version number,
+    ``None`` is returned.
 
     :param version_string: version as string object (e.g. '3.10.1')
     :type version_string: str or unicode
@@ -30,13 +32,21 @@ def parse_version_failsafe(version_string):
     else:
         uni_version = version_string
 
+    final_form = ''
+
     try:
         normalized_version = unicodedata.normalize('NFKD', uni_version)
         ascii_version = normalized_version.encode('ascii', 'ignore')
         final_form = ascii_version.decode('ascii')
         return Version(final_form)
-    except (UnicodeError, InvalidVersion):
-        return None
+    except InvalidVersion:
+        # Handle the special case of 1.x, 2.x or 1.0.x, 1.1.x
+        if final_form and '.x' in final_form:
+            return parse_version_failsafe(final_form.replace('.x', '.0'))
+    except UnicodeError:
+        pass
+
+    return None
 
 
 def comparable_version(version_string):
@@ -69,6 +79,9 @@ def sort_versions(version_list):
     """
     Take a list of Version models and return a sorted list.
 
+    This only considers versions with comparable version numbers.
+    It excludes versions like "latest" and "stable".
+
     :param version_list: list of Version models
     :type version_list: list(readthedocs.builds.models.Version)
 
diff --git a/readthedocs/rtd_tests/tests/projects/test_version_sorting.py b/readthedocs/rtd_tests/tests/projects/test_version_sorting.py
new file mode 100644
index 00000000000..2c8607d2e30
--- /dev/null
+++ b/readthedocs/rtd_tests/tests/projects/test_version_sorting.py
@@ -0,0 +1,67 @@
+from django.test import TestCase
+from django_dynamic_fixture import get
+
+from readthedocs.builds.constants import BRANCH
+from readthedocs.builds.models import Version
+from readthedocs.projects.models import Project
+from readthedocs.projects.templatetags.projects_tags import sort_version_aware
+
+
+class SortVersionsTest(TestCase):
+
+    def setUp(self):
+        self.project = get(Project)
+
+    def test_basic_sort(self):
+        identifiers = ['1.0', '2.0', '1.1', '1.9', '1.10']
+        for identifier in identifiers:
+            get(
+                Version,
+                project=self.project,
+                type=BRANCH,
+                identifier=identifier,
+                verbose_name=identifier,
+                slug=identifier,
+            )
+
+        versions = list(Version.objects.filter(project=self.project))
+        self.assertEqual(
+            ['latest', '2.0', '1.10', '1.9', '1.1', '1.0'],
+            [v.slug for v in sort_version_aware(versions)],
+        )
+
+    def test_sort_wildcard(self):
+        identifiers = ['1.0.x', '2.0.x', '1.1.x', '1.9.x', '1.10.x']
+        for identifier in identifiers:
+            get(
+                Version,
+                project=self.project,
+                type=BRANCH,
+                identifier=identifier,
+                verbose_name=identifier,
+                slug=identifier,
+            )
+
+        versions = list(Version.objects.filter(project=self.project))
+        self.assertEqual(
+            ['latest', '2.0.x', '1.10.x', '1.9.x', '1.1.x', '1.0.x'],
+            [v.slug for v in sort_version_aware(versions)],
+        )
+
+    def test_sort_alpha(self):
+        identifiers = ['banana', 'apple', 'carrot']
+        for identifier in identifiers:
+            get(
+                Version,
+                project=self.project,
+                type=BRANCH,
+                identifier=identifier,
+                verbose_name=identifier,
+                slug=identifier,
+            )
+
+        versions = list(Version.objects.filter(project=self.project))
+        self.assertEqual(
+            ['latest', 'carrot', 'banana', 'apple'],
+            [v.slug for v in sort_version_aware(versions)],
+        )