diff --git a/notebook/base/handlers.py b/notebook/base/handlers.py
index 30b1223aa..127a6ba20 100644
--- a/notebook/base/handlers.py
+++ b/notebook/base/handlers.py
@@ -32,7 +32,7 @@ from ipython_genutils.path import filefind
 from ipython_genutils.py3compat import string_types
 
 import notebook
-from notebook.utils import is_hidden, url_path_join, url_escape
+from notebook.utils import is_hidden, url_path_join, url_is_absolute, url_escape
 from notebook.services.security import csp_report_uri
 
 #-----------------------------------------------------------------------------
@@ -155,7 +155,10 @@ class IPythonHandler(AuthenticatedHandler):
     
     @property
     def mathjax_url(self):
-        return self.settings.get('mathjax_url', '')
+        url = self.settings.get('mathjax_url', '')
+        if not url or url_is_absolute(url):
+            return url
+        return url_path_join(self.base_url, url)
     
     @property
     def base_url(self):
diff --git a/notebook/notebookapp.py b/notebook/notebookapp.py
index bfbe467d1..c74e4eb48 100644
--- a/notebook/notebookapp.py
+++ b/notebook/notebookapp.py
@@ -658,9 +658,7 @@ class NotebookApp(JupyterApp):
     def _mathjax_url_default(self):
         if not self.enable_mathjax:
             return u''
-        static_url_prefix = self.tornado_settings.get("static_url_prefix",
-                         url_path_join(self.base_url, "static")
-        )
+        static_url_prefix = self.tornado_settings.get("static_url_prefix", "static")
         return url_path_join(static_url_prefix, 'components', 'MathJax', 'MathJax.js')
     
     def _mathjax_url_changed(self, name, old, new):
diff --git a/notebook/utils.py b/notebook/utils.py
index 9ba424ccf..ee9c6aceb 100644
--- a/notebook/utils.py
+++ b/notebook/utils.py
@@ -13,9 +13,10 @@ import sys
 from distutils.version import LooseVersion
 
 try:
-    from urllib.parse import quote, unquote
+    from urllib.parse import quote, unquote, urlparse
 except ImportError:
     from urllib import quote, unquote
+    from urlparse import urlparse
 
 from ipython_genutils import py3compat
 
@@ -39,6 +40,10 @@ def url_path_join(*pieces):
     if result == '//': result = '/'
     return result
 
+def url_is_absolute(url):
+    """Determine whether a given URL is absolute"""
+    return urlparse(url).path.startswith("/")
+
 def path2url(path):
     """Convert a local file path to a URL"""
     pieces = [ quote(p) for p in path.split(os.sep) ]