diff --git a/lib/galaxy/managers/history_contents.py b/lib/galaxy/managers/history_contents.py
index 70fb896de19..2b51ea99647 100644
--- a/lib/galaxy/managers/history_contents.py
+++ b/lib/galaxy/managers/history_contents.py
@@ -267,7 +267,14 @@ class HistoryContentsManager(containers.ContainerManagerMixin):
                     return False
         return True
 
-    def _union_of_contents_query(self, container, filters=None, limit=None, offset=None, order_by=None, **kwargs):
+    def _union_of_contents_query(self,
+                                 container,
+                                 filters=None,
+                                 limit=None,
+                                 offset=None,
+                                 order_by=None,
+                                 user_id=None,
+                                 **kwargs):
         """
         Returns a query for a limited and offset list of both types of contents,
         filtered and in some order.
@@ -285,8 +292,10 @@ class HistoryContentsManager(containers.ContainerManagerMixin):
         # note: I'm trying to keep these private functions as generic as possible in order to move them toward base later
 
         # query 1: create a union of common columns for which the component_classes can be filtered/limited
-        contained_query = self._contents_common_query_for_contained(container.id if container else None)
-        subcontainer_query = self._contents_common_query_for_subcontainer(container.id if container else None)
+        contained_query = self._contents_common_query_for_contained(history_id=container.id if container else None,
+                                                                    user_id=user_id)
+        subcontainer_query = self._contents_common_query_for_subcontainer(history_id=container.id if container else None,
+                                                                          user_id=user_id)
 
         filters = filters or []
         # Apply filters that are specific to a model
@@ -322,7 +331,7 @@ class HistoryContentsManager(containers.ContainerManagerMixin):
             columns.append(column)
         return columns
 
-    def _contents_common_query_for_contained(self, history_id=None):
+    def _contents_common_query_for_contained(self, history_id, user_id):
         component_class = self.contained_class
         # TODO: and now a join with Dataset - this is getting sad
         columns = self._contents_common_columns(component_class,
@@ -336,9 +345,15 @@ class HistoryContentsManager(containers.ContainerManagerMixin):
         subquery = subquery.join(model.Dataset, model.Dataset.id == component_class.dataset_id)
         if history_id:
             subquery = subquery.filter(component_class.history_id == history_id)
+        else:
+            # Make sure we only return items that are user-accessible by checking that they are in a history
+            # owned by the current user.
+            # TODO: move into filter mixin, and implement accessible logic as SQL query
+            subquery = subquery.filter(component_class.history_id == model.History.table.c.id,
+                                       model.History.table.c.user_id == user_id)
         return subquery
 
-    def _contents_common_query_for_subcontainer(self, history_id):
+    def _contents_common_query_for_subcontainer(self, history_id, user_id):
         component_class = self.subcontainer_class
         columns = self._contents_common_columns(component_class,
             history_content_type=literal('dataset_collection'),
@@ -358,6 +373,9 @@ class HistoryContentsManager(containers.ContainerManagerMixin):
             model.DatasetCollection.id == component_class.collection_id)
         if history_id:
             subquery = subquery.filter(component_class.history_id == history_id)
+        else:
+            subquery = subquery.filter(component_class.history_id == model.History.table.c.id,
+                                       model.History.table.c.user_id == user_id)
         return subquery
 
     def _get_union_type(self, union):
diff --git a/lib/galaxy/webapps/galaxy/api/datasets.py b/lib/galaxy/webapps/galaxy/api/datasets.py
index 28a70e76928..99eb617d768 100644
--- a/lib/galaxy/webapps/galaxy/api/datasets.py
+++ b/lib/galaxy/webapps/galaxy/api/datasets.py
@@ -115,7 +115,7 @@ class DatasetsController(BaseAPIController, UsesVisualizationMixin):
         if history_id:
             container = self.history_manager.get_accessible(self.decode_id(history_id), trans.user)
         contents = self.history_contents_manager.contents(
-            container=container, filters=filters, limit=limit, offset=offset, order_by=order_by
+            container=container, filters=filters, limit=limit, offset=offset, order_by=order_by, user_id=trans.user.id,
         )
         return [self.serializer_by_type[content.history_content_type].serialize_to_view(content, user=trans.user, trans=trans, view='summary') for content in contents]
 
diff --git a/test/api/test_datasets.py b/test/api/test_datasets.py
index 58f3fcd3103..013fcf2d10b 100644
--- a/test/api/test_datasets.py
+++ b/test/api/test_datasets.py
@@ -88,6 +88,14 @@ class DatasetsApiTestCase(api.ApiTestCase):
         self._assert_status_code_is(index_response, 400)
         assert index_response.json()['err_msg'] == 'bad op in filter'
 
+    def test_search_returns_only_accessible(self):
+        hda_id = self.dataset_populator.new_dataset(self.history_id)['id']
+        with self._different_user():
+            payload = {'limit': 10, 'offset': 0, 'q': ['history_content_type'], 'qv': ['dataset']}
+            index_response = self._get("datasets", payload).json()
+            for item in index_response:
+                assert hda_id != item['id']
+
     def test_show(self):
         hda1 = self.dataset_populator.new_dataset(self.history_id)
         show_response = self._get("datasets/%s" % (hda1["id"]))