diff --git a/.eslintrc.json b/.eslintrc.json
index 0f970db39f..2e414f1674 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -92,6 +92,7 @@
         "notifications": false,
         "message_flags": false,
         "bot_data": false,
+        "stream_sort": false,
         "stream_list": false,
         "stream_popover": false,
         "narrow": false,
diff --git a/frontend_tests/node_tests/stream_list.js b/frontend_tests/node_tests/stream_list.js
index a23708cf48..df7ad68c5b 100644
--- a/frontend_tests/node_tests/stream_list.js
+++ b/frontend_tests/node_tests/stream_list.js
@@ -9,6 +9,7 @@ add_dependencies({
     narrow: 'js/narrow',
     stream_color: 'js/stream_color',
     stream_data: 'js/stream_data',
+    stream_sort: 'js/stream_sort',
     subs: 'js/subs',
     templates: 'js/templates',
     unread: 'js/unread',
@@ -204,6 +205,17 @@ function clear_filters() {
 
     stream_list.build_stream_list();
 
+    var streams = global.stream_sort.get_streams().slice(0, 6);
+
+    assert.deepEqual(streams, [
+        'devel',
+        'Rome',
+        'test',
+        'Denmark',
+        'social',
+        'announce',
+    ]);
+
     // verify pinned streams are still sorted by lowercase name
     // i.e. not affected by sort_recent set to true
     assert.equal(devel_li.next().find('[ data-name="Rome"]').length, 1);
diff --git a/static/js/stream_list.js b/static/js/stream_list.js
index 14b1c801a6..1e09fc7292 100644
--- a/static/js/stream_list.js
+++ b/static/js/stream_list.js
@@ -3,8 +3,6 @@ var stream_list = (function () {
 var exports = {};
 
 var zoomed_stream = '';
-var previous_sort_order;
-var previous_unpinned_order;
 
 function update_count_in_dom(unread_count_elem, count) {
     var count_span = unread_count_elem.find('.count');
@@ -27,32 +25,6 @@ function update_count_in_dom(unread_count_elem, count) {
     value_span.text(count);
 }
 
-function filter_streams_by_search(streams) {
-    var search_box = $(".stream-list-filter");
-
-    var search_term = search_box.expectOne().val().trim();
-
-    if (search_term === '') {
-        return streams;
-    }
-
-    var search_terms = search_term.toLowerCase().split(",");
-    search_terms = _.map(search_terms, function (s) {
-        return s.trim();
-    });
-
-    var filtered_streams = _.filter(streams, function (stream) {
-        return _.any(search_terms, function (search_term) {
-            var lower_stream_name = stream.toLowerCase().split(" ");
-            return _.any(lower_stream_name, function (name) {
-                return name.indexOf(search_term) === 0;
-            });
-        });
-    });
-
-    return filtered_streams;
-}
-
 exports.stream_sidebar = (function () {
     var self = {};
 
@@ -93,11 +65,21 @@ exports.stream_sidebar = (function () {
     return self;
 }());
 
+function get_search_term() {
+    var search_box = $(".stream-list-filter");
+    var search_term = search_box.expectOne().val().trim();
+    return search_term;
+}
+
 exports.remove_sidebar_row = function (stream_id) {
     exports.stream_sidebar.remove_row(stream_id);
-    // We need to make sure we resort if the removed sub gets added again
-    previous_sort_order = undefined;
-    previous_unpinned_order = undefined;
+
+    // We call sort_groups to update our list of streams,
+    // even though we don't use the result, since we can
+    // just remove the row.  (The list of streams will
+    // be used by things like typeahead and hotkeys to
+    // advance to the next stream.)
+    stream_sort.sort_groups(get_search_term());
 };
 
 exports.create_initial_sidebar_rows = function () {
@@ -121,63 +103,39 @@ exports.build_stream_list = function () {
         return;
     }
 
-    streams = filter_streams_by_search(streams);
+    // The main logic to build the list is in stream_sort.js, and
+    // we get three lists of streams (pinned/normal/dormant).
+    var stream_groups = stream_sort.sort_groups(get_search_term());
+
+    if (stream_groups.same_as_before) {
+        return;
+    }
 
-    var sort_recent = (streams.length > 40);
-    var pinned_streams = [];
-    var unpinned_streams = [];
     var parent = $('#stream_filters');
     var elems = [];
 
     function add_sidebar_li(stream) {
         var sub = stream_data.get_sub(stream);
         var sidebar_row = exports.stream_sidebar.get_row(sub.stream_id);
-        if (sort_recent) {
+        if (stream_groups.sort_recent) {
             sidebar_row.update_whether_active();
         }
         elems.push(sidebar_row.get_li().get(0));
     }
 
-    _.each(streams, function (stream) {
-        var pinned = stream_data.get_sub(stream).pin_to_top;
-        if (pinned) {
-            pinned_streams.push(stream);
-        } else {
-            unpinned_streams.push(stream);
-        }
-    });
-
-    pinned_streams.sort(util.strcmp);
-
-    unpinned_streams.sort(function (a, b) {
-        if (sort_recent) {
-            if (stream_data.is_active(b) && ! stream_data.is_active(a)) {
-                return 1;
-            } else if (! stream_data.is_active(b) && stream_data.is_active(a)) {
-                return -1;
-            }
-        }
-        return util.strcmp(a, b);
-    });
-
-    streams = pinned_streams.concat(unpinned_streams);
-
-    if (previous_sort_order !== undefined &&
-        util.array_compare(previous_sort_order, streams) &&
-        util.array_compare(previous_unpinned_order, unpinned_streams)) {
-        return;
-    }
-    previous_sort_order = streams;
-    previous_unpinned_order = unpinned_streams;
     parent.empty();
 
-    if (pinned_streams.length > 0) {
-        _.each(pinned_streams, add_sidebar_li);
+    _.each(stream_groups.pinned_streams, add_sidebar_li);
+
+    if (stream_groups.pinned_streams.length > 0) {
         elems.push($('<hr class="pinned-stream-split">').get(0));
     }
-    if (unpinned_streams.length > 0) {
-        _.each(unpinned_streams, add_sidebar_li);
-    }
+
+    _.each(stream_groups.normal_streams, add_sidebar_li);
+
+    // TODO: Add a divider here if there are dormant streams.
+
+    _.each(stream_groups.dormant_streams, add_sidebar_li);
 
     $(elems).appendTo(parent);
 };
diff --git a/static/js/stream_sort.js b/static/js/stream_sort.js
new file mode 100644
index 0000000000..8f700650d2
--- /dev/null
+++ b/static/js/stream_sort.js
@@ -0,0 +1,98 @@
+var stream_sort = (function () {
+
+var exports = {};
+
+var previous_pinned;
+var previous_normal;
+var previous_dormant;
+var all_streams = [];
+
+exports.get_streams = function () {
+    // Right now this is only used for testing, but we should
+    // use it for things like hotkeys that cycle through streams.
+    return all_streams;
+};
+
+function filter_streams_by_search(streams, search_term) {
+    if (search_term === '') {
+        return streams;
+    }
+
+    var search_terms = search_term.toLowerCase().split(",");
+    search_terms = _.map(search_terms, function (s) {
+        return s.trim();
+    });
+
+    var filtered_streams = _.filter(streams, function (stream) {
+        return _.any(search_terms, function (search_term) {
+            var lower_stream_name = stream.toLowerCase().split(" ");
+            return _.any(lower_stream_name, function (name) {
+                return name.indexOf(search_term) === 0;
+            });
+        });
+    });
+
+    return filtered_streams;
+}
+
+exports.sort_groups = function (search_term) {
+    var streams = stream_data.subscribed_streams();
+    if (streams.length === 0) {
+        return;
+    }
+
+    streams = filter_streams_by_search(streams, search_term);
+
+    var sort_recent = (streams.length > 40);
+
+    function is_normal(stream) {
+        return !sort_recent || stream_data.is_active(stream);
+    }
+
+    var pinned_streams = [];
+    var normal_streams = [];
+    var dormant_streams = [];
+
+    _.each(streams, function (stream) {
+        var pinned = stream_data.get_sub(stream).pin_to_top;
+        if (pinned) {
+            pinned_streams.push(stream);
+        } else if (is_normal(stream)) {
+            normal_streams.push(stream);
+        } else {
+            dormant_streams.push(stream);
+        }
+    });
+
+    pinned_streams.sort(util.strcmp);
+    normal_streams.sort(util.strcmp);
+    dormant_streams.sort(util.strcmp);
+
+    var same_as_before =  (
+        previous_pinned !== undefined &&
+        util.array_compare(previous_pinned, pinned_streams) &&
+        util.array_compare(previous_normal, normal_streams) &&
+        util.array_compare(previous_dormant, dormant_streams));
+
+    if (!same_as_before) {
+        previous_pinned = pinned_streams;
+        previous_normal = normal_streams;
+        previous_dormant = dormant_streams;
+
+        all_streams = pinned_streams.concat(normal_streams, dormant_streams);
+    }
+
+    return {
+        same_as_before: same_as_before,
+        pinned_streams: pinned_streams,
+        normal_streams: normal_streams,
+        dormant_streams: dormant_streams,
+        sort_recent: sort_recent,
+    };
+};
+
+return exports;
+}());
+if (typeof module !== 'undefined') {
+    module.exports = stream_sort;
+}
diff --git a/zproject/settings.py b/zproject/settings.py
index e90124bdf1..a60e6d23e0 100644
--- a/zproject/settings.py
+++ b/zproject/settings.py
@@ -846,6 +846,7 @@ JS_SPECS = {
             'js/unread.js',
             'js/topic_list.js',
             'js/pm_list.js',
+            'js/stream_sort.js',
             'js/stream_list.js',
             'js/filter.js',
             'js/message_list_view.js',