diff --git a/autotests/libinput/touch_event_test.cpp b/autotests/libinput/touch_event_test.cpp
--- a/autotests/libinput/touch_event_test.cpp
+++ b/autotests/libinput/touch_event_test.cpp
@@ -40,6 +40,7 @@
     void testType();
     void testAbsoluteMotion_data();
     void testAbsoluteMotion();
+    void testNoAssignedSlot();
 
 private:
     libinput_device *m_nativeDevice = nullptr;
@@ -126,5 +127,19 @@
     QCOMPARE(te->absolutePos(QSize(1280, 1024)), QPointF(640, 512));
 }
 
+void TestLibinputTouchEvent::testNoAssignedSlot()
+{
+    // this test verifies that touch events without an assigned slot get id == 0
+    libinput_event_touch *touchEvent = new libinput_event_touch;
+    touchEvent->type = LIBINPUT_EVENT_TOUCH_UP;
+    touchEvent->device = m_nativeDevice;
+    // touch events without an assigned slot have slot == -1
+    touchEvent->slot = -1;
+
+    QScopedPointer<Event> event(Event::create(touchEvent));
+    QVERIFY(dynamic_cast<TouchEvent*>(event.data()));
+    QCOMPARE(dynamic_cast<TouchEvent*>(event.data())->id(), 0);
+}
+
 QTEST_GUILESS_MAIN(TestLibinputTouchEvent)
 #include "touch_event_test.moc"
diff --git a/libinput/events.cpp b/libinput/events.cpp
--- a/libinput/events.cpp
+++ b/libinput/events.cpp
@@ -225,7 +225,10 @@
 qint32 TouchEvent::id() const
 {
     Q_ASSERT(type() != LIBINPUT_EVENT_TOUCH_CANCEL && type() != LIBINPUT_EVENT_TOUCH_FRAME);
-    return libinput_event_touch_get_slot(m_touchEvent);
+
+    const qint32 slot = libinput_event_touch_get_slot(m_touchEvent);
+
+    return slot == -1 ? 0 : slot;
 }
 
 GestureEvent::GestureEvent(libinput_event *event, libinput_event_type type)