diff --git a/awscli/arguments.py b/awscli/arguments.py
index 96ac5de17150..90b9cbb1b6c7 100644
--- a/awscli/arguments.py
+++ b/awscli/arguments.py
@@ -449,7 +449,7 @@ def add_to_parser(self, parser):
         cli_name = self.cli_name
         parser.add_argument(
             cli_name,
-            help=self.documentation,
+            help=self.documentation.replace('%', '%%'),
             type=self.cli_type,
             required=self.required,
         )
@@ -600,7 +600,7 @@ def add_to_arg_table(self, argument_table):
     def add_to_parser(self, parser):
         parser.add_argument(
             self.cli_name,
-            help=self.documentation,
+            help=self.documentation.replace('%', '%%'),
             action=self._action,
             default=self._default,
             dest=self._destination,
diff --git a/tests/unit/test_argprocess.py b/tests/unit/test_argprocess.py
index fe5eb531f301..59c0d93ff83c 100644
--- a/tests/unit/test_argprocess.py
+++ b/tests/unit/test_argprocess.py
@@ -33,6 +33,7 @@
 from awscli.help import OperationHelpCommand
 from awscli.paramfile import LOCAL_PREFIX_MAP, URIArgumentHandler
 from awscli.testutils import BaseCLIDriverTest, mock, temporary_file, unittest
+from awscli.argparser import ArgTableArgParser
 
 
 # These tests use real service types so that we can
@@ -968,5 +969,39 @@ def test_json_value_decode_error(self):
             unpack_cli_arg(self.p, value)
 
 
+class TestArgumentPercentEscaping(BaseArgProcessTest):
+    def _test_percent_escaping(self, arg_type, arg_class, doc_string):
+        argument = self.create_argument(
+            {
+                'Test': {
+                    'type': arg_type,
+                    'documentation': doc_string,
+                }
+            }
+        )
+        arg = arg_class(
+            'test-arg',
+            argument.argument_model.members['Test'],
+            mock.Mock(),
+            mock.Mock(),
+            is_required=False,
+        )
+        arg_table = {arg.name: arg}
+        parser = ArgTableArgParser(arg_table)
+        help_output = parser.format_help()
+        self.assertIn(doc_string, help_output)
+
+    def test_cli_argument_escapes_percent(self):
+        self._test_percent_escaping('string', CLIArgument, 'Symbols: % ^ & *')
+
+    def test_boolean_argument_escapes_percent(self):
+        self._test_percent_escaping('boolean', BooleanArgument, 'Symbols: % ^ & *')
+
+    def test_cli_argument_escapes_url_encoded_percent(self):
+        self._test_percent_escaping('string', CLIArgument, 'File: test%28file%29.png')
+
+    def test_boolean_argument_escapes_url_encoded_percent(self):
+        self._test_percent_escaping('boolean', BooleanArgument, 'File: test%28file%29.png')
+
 if __name__ == '__main__':
     unittest.main()