diff --git a/django/http/utils.py b/django/http/utils.py
index 5eea23907b..01808648ba 100644
--- a/django/http/utils.py
+++ b/django/http/utils.py
@@ -76,7 +76,8 @@ def fix_IE_for_vary(request, response):
 
     # The first part of the Content-Type field will be the MIME type,
     # everything after ';', such as character-set, can be ignored.
-    if response['Content-Type'].split(';')[0] not in safe_mime_types:
+    mime_type = response.get('Content-Type', '').partition(';')[0]
+    if mime_type not in safe_mime_types:
         try:
             del response['Vary']
         except KeyError:
diff --git a/tests/regressiontests/utils/http.py b/tests/regressiontests/utils/http.py
index 3f3a36cef7..4aed880a7c 100644
--- a/tests/regressiontests/utils/http.py
+++ b/tests/regressiontests/utils/http.py
@@ -1,6 +1,8 @@
 from django.utils import http
 from django.utils import unittest
 from django.utils.datastructures import MultiValueDict
+from django.http import HttpResponse, utils
+from django.test import RequestFactory
 
 class TestUtilsHttp(unittest.TestCase):
 
@@ -51,3 +53,48 @@ class TestUtilsHttp(unittest.TestCase):
             'position=Developer&name=Adrian&name=Simon'
         ]
         self.assertTrue(result in acceptable_results)
+
+    def test_fix_IE_for_vary(self):
+        """
+        Regression for #16632.
+
+        `fix_IE_for_vary` shouldn't crash when there's no Content-Type header.
+        """
+
+        # functions to generate responses
+        def response_with_unsafe_content_type():
+            r = HttpResponse(content_type="text/unsafe")
+            r['Vary'] = 'Cookie'
+            return r
+
+        def no_content_response_with_unsafe_content_type():
+            # 'Content-Type' always defaulted, so delete it
+            r = response_with_unsafe_content_type()
+            del r['Content-Type']
+            return r
+
+        # request with & without IE user agent
+        rf = RequestFactory()
+        request = rf.get('/')
+        ie_request = rf.get('/', HTTP_USER_AGENT='MSIE')
+
+        # not IE, unsafe_content_type
+        response = response_with_unsafe_content_type()
+        utils.fix_IE_for_vary(request, response)
+        self.assertTrue('Vary' in response)
+
+        # IE, unsafe_content_type
+        response = response_with_unsafe_content_type()
+        utils.fix_IE_for_vary(ie_request, response)
+        self.assertFalse('Vary' in response)
+
+        # not IE, no_content
+        response = no_content_response_with_unsafe_content_type()
+        utils.fix_IE_for_vary(request, response)
+        self.assertTrue('Vary' in response)
+
+        # IE, no_content
+        response = no_content_response_with_unsafe_content_type()
+        utils.fix_IE_for_vary(ie_request, response)
+        self.assertFalse('Vary' in response)
+