diff --git a/django/template/defaultfilters.py b/django/template/defaultfilters.py
index 4b720093b3..d8e7e91efe 100644
--- a/django/template/defaultfilters.py
+++ b/django/template/defaultfilters.py
@@ -11,9 +11,10 @@ except ImportError:
 from django.template import Variable, Library
 from django.conf import settings
 from django.utils import formats
-from django.utils.translation import ugettext, ungettext
 from django.utils.encoding import force_unicode, iri_to_uri
+from django.utils.html import conditional_escape
 from django.utils.safestring import mark_safe, SafeData
+from django.utils.translation import ugettext, ungettext
 
 register = Library()
 
@@ -496,10 +497,9 @@ def join(value, arg, autoescape=None):
     """
     value = map(force_unicode, value)
     if autoescape:
-        from django.utils.html import conditional_escape
         value = [conditional_escape(v) for v in value]
     try:
-        data = arg.join(value)
+        data = conditional_escape(arg).join(value)
     except AttributeError: # fail silently but nicely
         return value
     return mark_safe(data)
diff --git a/tests/regressiontests/templates/filters.py b/tests/regressiontests/templates/filters.py
index 3d6284e881..d351c550b7 100644
--- a/tests/regressiontests/templates/filters.py
+++ b/tests/regressiontests/templates/filters.py
@@ -328,7 +328,12 @@ def get_filter_tests():
         'join03': (r'{{ a|join:" & " }}', {'a': ['alpha', 'beta & me']}, 'alpha & beta & me'),
         'join04': (r'{% autoescape off %}{{ a|join:" & " }}{% endautoescape %}', {'a': ['alpha', 'beta & me']}, 'alpha & beta & me'),
 
-
+        # Test that joining with unsafe joiners don't result in unsafe strings (#11377)
+        'join05': (r'{{ a|join:var }}', {'a': ['alpha', 'beta & me'], 'var': ' & '}, 'alpha & beta & me'), 
+        'join06': (r'{{ a|join:var }}', {'a': ['alpha', 'beta & me'], 'var': mark_safe(' & ')}, 'alpha & beta & me'), 
+        'join07': (r'{{ a|join:var|lower }}', {'a': ['Alpha', 'Beta & me'], 'var': ' & ' }, 'alpha & beta & me'), 
+        'join08': (r'{{ a|join:var|lower }}', {'a': ['Alpha', 'Beta & me'], 'var': mark_safe(' & ')}, 'alpha & beta & me'), 
+        
         'date01': (r'{{ d|date:"m" }}', {'d': datetime(2008, 1, 1)}, '01'),
         'date02': (r'{{ d|date }}', {'d': datetime(2008, 1, 1)}, 'Jan. 1, 2008'),
         #Ticket 9520: Make sure |date doesn't blow up on non-dates