diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 76f14f7838..c1201fa85e 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -7,6 +7,7 @@ Changelog
  * New class-based configuration for media embeds (Karl Hobley)
  * The admin interface now displays a title of the latest draft (Mikalai Radchuk)
  * Added multi-select form field to the form builder (dwasyl)
+ * Improved performance of sitemap generation (Levi Adler)
  * Fix: FieldBlocks in StreamField now call the field's `prepare_value` method (Tim Heap)
  * Fix: Initial disabled state of InlinePanel add button is now set correctly on non-default tabs (Matthew Downey)
  * Fix: Redirects with unicode characters now work (Rich Brennan)
diff --git a/CONTRIBUTORS.rst b/CONTRIBUTORS.rst
index fefcfe55bf..b26ce8e09e 100644
--- a/CONTRIBUTORS.rst
+++ b/CONTRIBUTORS.rst
@@ -246,6 +246,7 @@ Contributors
 * Paul Kamp
 * dwasyl
 * Eugene Morozov
+* Levi Adler
 
 Translators
 ===========
diff --git a/docs/releases/1.12.rst b/docs/releases/1.12.rst
index 0fea4b807f..80a0327002 100644
--- a/docs/releases/1.12.rst
+++ b/docs/releases/1.12.rst
@@ -23,6 +23,7 @@ Other features
 
  * The admin interface now displays a title of the latest draft (Mikalai Radchuk)
  * Added multi-select form field to the form builder (dwasyl)
+ * Improved performance of sitemap generation (Levi Adler)
 
 Bug fixes
 ~~~~~~~~~
diff --git a/wagtail/contrib/wagtailsitemaps/sitemap_generator.py b/wagtail/contrib/wagtailsitemaps/sitemap_generator.py
index f903a1aa82..c2cde386f0 100644
--- a/wagtail/contrib/wagtailsitemaps/sitemap_generator.py
+++ b/wagtail/contrib/wagtailsitemaps/sitemap_generator.py
@@ -9,11 +9,9 @@ class Sitemap(DjangoSitemap):
         self.site = site
 
     def location(self, obj):
-        return obj.specific.url
+        return obj.url
 
     def lastmod(self, obj):
-        obj = obj.specific
-
         # fall back on latest_revision_created_at if last_published_at is null
         # (for backwards compatibility from before last_published_at was added)
         return (obj.last_published_at or obj.latest_revision_created_at)
@@ -25,14 +23,15 @@ class Sitemap(DjangoSitemap):
             .get_descendants(inclusive=True)
             .live()
             .public()
-            .order_by('path'))
+            .order_by('path')
+            .specific())
 
     def _urls(self, page, protocol, domain):
         urls = []
         last_mods = set()
 
         for item in self.paginator.page(page).object_list:
-            for url_info in item.specific.get_sitemap_urls():
+            for url_info in item.get_sitemap_urls():
                 urls.append(url_info)
                 last_mods.add(url_info.get('lastmod'))
 
diff --git a/wagtail/contrib/wagtailsitemaps/tests.py b/wagtail/contrib/wagtailsitemaps/tests.py
index 9fa2147b82..4855280eb8 100644
--- a/wagtail/contrib/wagtailsitemaps/tests.py
+++ b/wagtail/contrib/wagtailsitemaps/tests.py
@@ -54,9 +54,9 @@ class TestSitemapGenerator(TestCase):
         sitemap = Sitemap(self.site)
         pages = sitemap.items()
 
-        self.assertIn(self.child_page.page_ptr, pages)
-        self.assertNotIn(self.unpublished_child_page.page_ptr, pages)
-        self.assertNotIn(self.protected_child_page.page_ptr, pages)
+        self.assertIn(self.child_page.page_ptr.specific, pages)
+        self.assertNotIn(self.unpublished_child_page.page_ptr.specific, pages)
+        self.assertNotIn(self.protected_child_page.page_ptr.specific, pages)
 
     def test_get_urls(self):
         request = RequestFactory().get('/sitemap.xml')
@@ -108,6 +108,34 @@ class TestSitemapGenerator(TestCase):
         ][0]
         self.assertEqual(child_page_lastmod, datetime.datetime(2017, 2, 1, 12, 0, 0, tzinfo=pytz.utc))
 
+    def test_latest_lastmod(self):
+        # give the homepage a lastmod
+        self.home_page.last_published_at = datetime.datetime(2017, 3, 1, 12, 0, 0, tzinfo=pytz.utc)
+        self.home_page.save()
+
+        request = RequestFactory().get('/sitemap.xml')
+        req_protocol = request.scheme
+        req_site = get_current_site(request)
+
+        sitemap = Sitemap(self.site)
+        sitemap.get_urls(1, req_site, req_protocol)
+
+        self.assertEqual(sitemap.latest_lastmod, datetime.datetime(2017, 3, 1, 12, 0, 0, tzinfo=pytz.utc))
+
+    def test_latest_lastmod_missing(self):
+        # ensure homepage does not have lastmod
+        self.home_page.last_published_at = None
+        self.home_page.save()
+
+        request = RequestFactory().get('/sitemap.xml')
+        req_protocol = request.scheme
+        req_site = get_current_site(request)
+
+        sitemap = Sitemap(self.site)
+        sitemap.get_urls(1, req_site, req_protocol)
+
+        self.assertFalse(hasattr(sitemap, 'latest_lastmod'))
+
 
 class TestIndexView(TestCase):
     def test_index_view(self):