diff --git a/src/akonadi/akonadicontextqueries.cpp b/src/akonadi/akonadicontextqueries.cpp
--- a/src/akonadi/akonadicontextqueries.cpp
+++ b/src/akonadi/akonadicontextqueries.cpp
@@ -55,7 +55,28 @@
     Akonadi::Tag tag = m_serializer->createTagFromContext(context);
     auto fetch = m_helpers->fetchItems(tag);
     auto predicate = [this, context] (const Akonadi::Item &item) {
-        return m_serializer->isContextChild(context, item);
+        if (!m_serializer->isContextChild(context, item))
+            return false;
+
+        const auto items = m_cache->items(item.parentCollection());
+        auto currentItem = item;
+        auto parentUid = m_serializer->relatedUidFromItem(currentItem);
+        while (!parentUid.isEmpty()) {
+            const auto parent = std::find_if(items.cbegin(), items.cend(),
+                                             [this, parentUid] (const Akonadi::Item &item) {
+                                                 return m_serializer->itemUid(item) == parentUid;
+                                             });
+            if (parent == items.cend())
+                break;
+
+            if (m_serializer->isContextChild(context, *parent))
+                return false;
+
+            currentItem = *parent;
+            parentUid = m_serializer->relatedUidFromItem(currentItem);
+        }
+
+        return true;
     };
     auto &query = m_findToplevel[tag.id()];
     m_integrator->bind("ContextQueries::findTopLevelTasks", query, fetch, predicate);
diff --git a/tests/units/akonadi/akonadicontextqueriestest.cpp b/tests/units/akonadi/akonadicontextqueriestest.cpp
--- a/tests/units/akonadi/akonadicontextqueriestest.cpp
+++ b/tests/units/akonadi/akonadicontextqueriestest.cpp
@@ -240,6 +240,52 @@
         QCOMPARE(result->data().at(1)->title(), QStringLiteral("44"));
     }
 
+    void shouldNotListContextTasksTwiceIfTheyHaveAParentInTheSameContext()
+    {
+        // GIVEN
+        AkonadiFakeData data;
+
+        // One top level collection
+        data.createCollection(GenCollection().withId(42).withRootAsParent().withTaskContent());
+
+        // One context tag
+        data.createTag(GenTag().withId(42).withName(QStringLiteral("42")).asContext());
+
+        // Five tasks in the collection, two related to context, three not, all forming an ancestry line
+        data.createItem(GenTodo().withParent(42).withId(42).withTitle(QStringLiteral("42")).withUid("42"));
+        data.createItem(GenTodo().withParent(42).withId(43).withTitle(QStringLiteral("43")).withUid("43").withParentUid("42").withTags({42}));
+        data.createItem(GenTodo().withParent(42).withId(44).withTitle(QStringLiteral("44")).withUid("44").withParentUid("43"));
+        data.createItem(GenTodo().withParent(42).withId(45).withTitle(QStringLiteral("45")).withUid("45").withParentUid("44").withTags({42}));
+        data.createItem(GenTodo().withParent(42).withId(46).withTitle(QStringLiteral("46")).withUid("46").withParentUid("45"));
+
+        // WHEN
+        auto serializer = Akonadi::SerializerInterface::Ptr(new Akonadi::Serializer);
+        auto cache = Akonadi::Cache::Ptr::create(serializer, Akonadi::MonitorInterface::Ptr(data.createMonitor()));
+        QScopedPointer<Domain::ContextQueries> queries(new Akonadi::ContextQueries(createCachingStorage(data, cache),
+                                                                                   Akonadi::Serializer::Ptr(new Akonadi::Serializer),
+                                                                                   Akonadi::MonitorInterface::Ptr(data.createMonitor()),
+                                                                                   cache));
+
+        auto context = serializer->createContextFromTag(data.tag(42));
+        auto result = queries->findTopLevelTasks(context);
+        result->data();
+        result = queries->findTopLevelTasks(context); // Should not cause any problem or wrong data
+
+        // THEN
+        QVERIFY(result->data().isEmpty());
+        TestHelpers::waitForEmptyJobQueue();
+
+        QCOMPARE(result->data().size(), 1);
+        QCOMPARE(result->data().at(0)->title(), QStringLiteral("43"));
+
+        // Should not change anything
+        result = queries->findTopLevelTasks(context);
+        TestHelpers::waitForEmptyJobQueue();
+
+        QCOMPARE(result->data().size(), 1);
+        QCOMPARE(result->data().at(0)->title(), QStringLiteral("43"));
+    }
+
     void shouldReactToItemAddsForTopLevelTask()
     {
         // GIVEN