diff --git a/letsencrypt/acme/errors.py b/letsencrypt/acme/errors.py
index a65a8649a..a70271894 100644
--- a/letsencrypt/acme/errors.py
+++ b/letsencrypt/acme/errors.py
@@ -6,7 +6,7 @@ class Error(Exception):
 class ValidationError(Error):
     """ACME message validation error."""
 
-class UnrecognnizedMessageTypeError(ValidationError):
+class UnrecognizedMessageTypeError(ValidationError):
     """Unrecognized ACME message type error."""
 
 class SchemaValidationError(ValidationError):
diff --git a/letsencrypt/acme/messages.py b/letsencrypt/acme/messages.py
index 71d243406..c91c95f59 100644
--- a/letsencrypt/acme/messages.py
+++ b/letsencrypt/acme/messages.py
@@ -33,7 +33,7 @@ class Message(util.JSONDeSerializable, util.ImmutableMap):
         """Get JSON serializable object.
 
         :returns: Serializable JSON object representing ACME message.
-            :meth:`validate` will almost certianly not work, due to reasons
+            :meth:`validate` will almost certainly not work, due to reasons
             explained in :class:`letsencrypt.acme.interfaces.IJSONSerializable`.
         :rtype: dict
 
@@ -80,7 +80,7 @@ class Message(util.JSONDeSerializable, util.ImmutableMap):
         try:
             msg_cls = cls.TYPES[msg_type]
         except KeyError:
-            raise errors.UnrecognnizedMessageTypeError(msg_type)
+            raise errors.UnrecognizedMessageTypeError(msg_type)
 
         if validate:
             msg_cls.validate_json(jobj)
diff --git a/letsencrypt/acme/messages_test.py b/letsencrypt/acme/messages_test.py
index 20ecd9919..0820c8e73 100644
--- a/letsencrypt/acme/messages_test.py
+++ b/letsencrypt/acme/messages_test.py
@@ -65,7 +65,7 @@ class MessageTest(unittest.TestCase):
         self.assertRaises(errors.ValidationError, self._from_json, {})
 
     def test_from_json_unknown_type_fails(self):
-        self.assertRaises(errors.UnrecognnizedMessageTypeError,
+        self.assertRaises(errors.UnrecognizedMessageTypeError,
                           self._from_json, {'type': 'bar'})
 
     @mock.patch('letsencrypt.acme.messages.Message.TYPES')