diff --git a/docs/x509.rst b/docs/x509.rst
index eed88b0..0ce9016 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -964,6 +964,11 @@
 
         Returns the OID.
 
+.. class:: UnsupportedGeneralNameType
+
+    This is raised when a certificate contains an unsupported general name
+    type in an extension.
+
 
 .. _`public key infrastructure`: https://en.wikipedia.org/wiki/Public_key_infrastructure
 .. _`TLS`: https://en.wikipedia.org/wiki/Transport_Layer_Security
diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index dcde5e7..affb79d 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -63,6 +63,13 @@
     if gn.type == backend._lib.GEN_DNS:
         data = backend._ffi.buffer(gn.d.dNSName.data, gn.d.dNSName.length)[:]
         return x509.DNSName(idna.decode(data))
+    else:
+        # otherName, x400Address or ediPartyName
+        raise x509.UnsupportedGeneralNameType(
+            "{0} is not a supported type".format(
+                x509._GENERAL_NAMES.get(gn.type, gn.type)
+            )
+        )
 
 
 @utils.register_interface(x509.Certificate)
diff --git a/src/cryptography/x509.py b/src/cryptography/x509.py
index 898ab6c..3dc066f 100644
--- a/src/cryptography/x509.py
+++ b/src/cryptography/x509.py
@@ -70,6 +70,19 @@
 }
 
 
+_GENERAL_NAMES = {
+    0: "otherName",
+    1: "rfc822Name",
+    2: "dNSName",
+    3: "x400Address",
+    4: "directoryName",
+    5: "ediPartyName",
+    6: "uniformResourceIdentifier",
+    7: "iPAddress",
+    8: "registeredID",
+}
+
+
 class Version(Enum):
     v1 = 0
     v3 = 2
@@ -115,6 +128,10 @@
         self.oid = oid
 
 
+class UnsupportedGeneralNameType(Exception):
+    pass
+
+
 class NameAttribute(object):
     def __init__(self, oid, value):
         if not isinstance(oid, ObjectIdentifier):
diff --git a/tests/test_x509_ext.py b/tests/test_x509_ext.py
index a7e0415..5f175c4 100644
--- a/tests/test_x509_ext.py
+++ b/tests/test_x509_ext.py
@@ -757,3 +757,14 @@
 
         dns = san.get_values_for_type(x509.DNSName)
         assert dns == [u"www.cryptography.io", u"cryptography.io"]
+
+    def test_unsupported_other_name(self, backend):
+        cert = _load_cert(
+            os.path.join(
+                "x509", "custom", "san_other_name.pem"
+            ),
+            x509.load_pem_x509_certificate,
+            backend
+        )
+        with pytest.raises(x509.UnsupportedGeneralNameType):
+            cert.extensions