diff --git a/zerver/fixtures/narrow.json b/zerver/fixtures/narrow.json
index 9d8160bec4..af38c77317 100644
--- a/zerver/fixtures/narrow.json
+++ b/zerver/fixtures/narrow.json
@@ -227,5 +227,27 @@
                 "mentioned"
             ]
         ]
+    },
+    {
+        "accept_events":[
+            {
+                "message":null,
+                "flags": [],
+            }
+        ],
+        "reject_events":[
+            {
+                "message":null,
+                "flags":[
+                    "read"
+                ]
+            }
+        ],
+        "narrow":[
+            [
+                "is",
+                "unread"
+            ]
+        ]
     }
 ]
diff --git a/zerver/lib/narrow.py b/zerver/lib/narrow.py
index 3009c250ef..c60438c654 100644
--- a/zerver/lib/narrow.py
+++ b/zerver/lib/narrow.py
@@ -43,6 +43,9 @@ def build_narrow_filter(narrow):
             elif operator == "is" and operand in ["starred"]:
                 if operand not in flags:
                     return False
+            elif operator == "is" and operand == "unread":
+                if "read" in flags:
+                    return False
             elif operator == "is" and operand in ["alerted", "mentioned"]:
                 if "mentioned" not in flags:
                     return False
diff --git a/zerver/tests/test_narrow.py b/zerver/tests/test_narrow.py
index 29bff82e79..4efd09bcb2 100644
--- a/zerver/tests/test_narrow.py
+++ b/zerver/tests/test_narrow.py
@@ -112,6 +112,16 @@ class NarrowBuilderTest(ZulipTestCase):
             term = dict(operator='is', operand=operand)
             self._do_add_term_test(term, 'WHERE (flags & :flags_1) != :param_1')
 
+    def test_add_term_using_is_operator_and_unread_operand(self):
+        # type: () -> None
+        term = dict(operator='is', operand='unread')
+        self._do_add_term_test(term, 'WHERE (flags & :flags_1) = :param_1')
+
+    def test_add_term_using_is_operator_and_unread_operand_and_negated(self):  # NEGATED
+        # type: () -> None
+        term = dict(operator='is', operand='unread', negated=True)
+        self._do_add_term_test(term, 'WHERE (flags & :flags_1) != :param_1')
+
     def test_add_term_using_is_operator_non_private_operand_and_negated(self):  # NEGATED
         # type: () -> None
         for operand in ['starred', 'mentioned', 'alerted']:
@@ -335,7 +345,7 @@ class BuildNarrowFilterTest(TestCase):
         fixtures_path = os.path.join(os.path.dirname(__file__),
                                      '../fixtures/narrow.json')
         scenarios = ujson.loads(open(fixtures_path, 'r').read())
-        self.assertTrue(len(scenarios) == 8)
+        self.assertTrue(len(scenarios) == 9)
         for scenario in scenarios:
             narrow = scenario['narrow']
             accept_events = scenario['accept_events']
@@ -375,6 +385,12 @@ class IncludeHistoryTest(ZulipTestCase):
         ]
         self.assertFalse(ok_to_include_history(narrow, realm))
 
+        # History doesn't apply to unread messages.
+        narrow = [
+            dict(operator='is', operand='unread'),
+        ]
+        self.assertFalse(ok_to_include_history(narrow, realm))
+
         # If we are looking for something like starred messages, there is
         # no point in searching historical messages.
         narrow = [
diff --git a/zerver/views/messages.py b/zerver/views/messages.py
index 97d3a0fe7c..f0216254d4 100644
--- a/zerver/views/messages.py
+++ b/zerver/views/messages.py
@@ -133,6 +133,9 @@ class NarrowBuilder(object):
         elif operand == 'starred':
             cond = column("flags").op("&")(UserMessage.flags.starred.mask) != 0
             return query.where(maybe_negate(cond))
+        elif operand == 'unread':
+            cond = column("flags").op("&")(UserMessage.flags.read.mask) == 0
+            return query.where(maybe_negate(cond))
         elif operand == 'mentioned' or operand == 'alerted':
             cond = column("flags").op("&")(UserMessage.flags.mentioned.mask) != 0
             return query.where(maybe_negate(cond))