diff --git a/tests/test_binary_support_settings.py b/tests/test_binary_support_settings.py
new file mode 100644
index 000000000..adb257d55
--- /dev/null
+++ b/tests/test_binary_support_settings.py
@@ -0,0 +1,12 @@
+API_STAGE = "dev"
+APP_FUNCTION = "app"
+APP_MODULE = "tests.test_wsgi_binary_support_app"
+BINARY_SUPPORT = True
+CONTEXT_HEADER_MAPPINGS = {}
+DEBUG = "True"
+DJANGO_SETTINGS = None
+DOMAIN = "api.example.com"
+ENVIRONMENT_VARIABLES = {}
+LOG_LEVEL = "DEBUG"
+PROJECT_NAME = "binary_support_settings"
+COGNITO_TRIGGER_MAPPING = {}
diff --git a/tests/test_handler.py b/tests/test_handler.py
index eecb3dcab..ce38278b3 100644
--- a/tests/test_handler.py
+++ b/tests/test_handler.py
@@ -3,6 +3,7 @@
 
 from mock import Mock
 
+from tests.utils import is_base64
 from zappa.handler import LambdaHandler
 from zappa.utilities import merge_headers
 
@@ -225,6 +226,66 @@ def test_exception_handler_on_web_request(self):
         self.assertEqual(response["statusCode"], 500)
         mocked_exception_handler.assert_called()
 
+    def test_wsgi_script_binary_support_base64_behavior(self):
+        """
+        With Binary Support enabled, response mimetypes that are not text/* or application/json will be base64 encoded
+        """
+        lh = LambdaHandler("tests.test_binary_support_settings")
+
+        text_plain_event = {
+            "body": "",
+            "resource": "/{proxy+}",
+            "requestContext": {},
+            "queryStringParameters": {},
+            "headers": {
+                "Host": "1234567890.execute-api.us-east-1.amazonaws.com",
+            },
+            "pathParameters": {"proxy": "return/request/url"},
+            "httpMethod": "GET",
+            "stageVariables": {},
+            "path": "/textplain_mimetype_response1",
+        }
+
+        response = lh.handler(text_plain_event, None)
+
+        self.assertEqual(response["statusCode"], 200)
+        self.assertNotIn("isBase64Encoded", response)
+        self.assertFalse(is_base64(response["body"]))
+
+        text_arbitrary_event = {
+            **text_plain_event,
+            **{"path": "/textarbitrary_mimetype_response1"},
+        }
+
+        response = lh.handler(text_arbitrary_event, None)
+
+        self.assertEqual(response["statusCode"], 200)
+        self.assertNotIn("isBase64Encoded", response)
+        self.assertFalse(is_base64(response["body"]))
+
+        application_json_event = {
+            **text_plain_event,
+            **{"path": "/json_mimetype_response1"},
+        }
+
+        response = lh.handler(application_json_event, None)
+
+        self.assertEqual(response["statusCode"], 200)
+        self.assertNotIn("isBase64Encoded", response)
+        self.assertFalse(is_base64(response["body"]))
+
+        arbitrary_binary_event = {
+            **text_plain_event,
+            **{"path": "/arbitrarybinary_mimetype_response1"},
+        }
+
+        response = lh.handler(arbitrary_binary_event, None)
+
+        self.assertEqual(response["statusCode"], 200)
+        self.assertIn("isBase64Encoded", response)
+        self.assertTrue(response["isBase64Encoded"])
+        self.assertTrue(is_base64(response["body"]))
+
     def test_wsgi_script_on_cognito_event_request(self):
         """
         Ensure that requests sent by cognito behave sensibly
diff --git a/tests/test_wsgi_binary_support_app.py b/tests/test_wsgi_binary_support_app.py
new file mode 100644
index 000000000..ef0f62287
--- /dev/null
+++ b/tests/test_wsgi_binary_support_app.py
@@ -0,0 +1,31 @@
+###
+# This test application exists to confirm how Zappa handles WSGI application
+# _responses_ when Binary Support is enabled.
+###
+
+import io
+import json
+
+from flask import Flask, Response, send_file
+
+app = Flask(__name__)
+
+
+@app.route("/textplain_mimetype_response1", methods=["GET"])
+def text_mimetype_response_1():
+    return Response(response="OK", mimetype="text/plain")
+
+
+@app.route("/textarbitrary_mimetype_response1", methods=["GET"])
+def text_mimetype_response_2():
+    return Response(response="OK", mimetype="text/arbitary")
+
+
+@app.route("/json_mimetype_response1", methods=["GET"])
+def json_mimetype_response_1():
+    return Response(response=json.dumps({"some": "data"}), mimetype="application/json")
+
+
+@app.route("/arbitrarybinary_mimetype_response1", methods=["GET"])
+def arbitrary_mimetype_response_1():
+    return Response(response=b"some binary data", mimetype="arbitrary/binary_mimetype")
diff --git a/tests/utils.py b/tests/utils.py
index 31453e0ac..9a0f74943 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -1,3 +1,4 @@
+import base64
 import functools
 import os
 from contextlib import contextmanager
@@ -74,3 +75,14 @@ def stub_open(*args, **kwargs):
 
     with patch("__builtin__.open", stub_open):
         yield mock_open, mock_file
+
+
+def is_base64(test_string: str) -> bool:
+    # Taken from https://stackoverflow.com/a/45928164/3200002
+    try:
+        return (
+            base64.b64encode(base64.b64decode(test_string)).decode("utf-8")
+            == test_string
+        )
+    except Exception:
+        return False