diff --git a/moto/iot/models.py b/moto/iot/models.py
index 1b10c09f..ce7a4cf5 100644
--- a/moto/iot/models.py
+++ b/moto/iot/models.py
@@ -32,6 +32,7 @@ class FakeThing(BaseModel):
     def to_dict(self, include_default_client_id=False):
         obj = {
             'thingName': self.thing_name,
+            'thingArn': self.arn,
             'attributes': self.attributes,
             'version': self.version
         }
diff --git a/tests/test_iot/test_iot.py b/tests/test_iot/test_iot.py
index 19e11476..21361579 100644
--- a/tests/test_iot/test_iot.py
+++ b/tests/test_iot/test_iot.py
@@ -35,12 +35,14 @@ def test_things():
     res.should.have.key('things').which.should.have.length_of(1)
     for thing in res['things']:
         thing.should.have.key('thingName').which.should_not.be.none
+        thing.should.have.key('thingArn').which.should_not.be.none
 
     thing = client.update_thing(thingName=name, attributePayload={'attributes': {'k1': 'v1'}})
     res = client.list_things()
     res.should.have.key('things').which.should.have.length_of(1)
     for thing in res['things']:
         thing.should.have.key('thingName').which.should_not.be.none
+        thing.should.have.key('thingArn').which.should_not.be.none
     res['things'][0]['attributes'].should.have.key('k1').which.should.equal('v1')
 
     thing = client.describe_thing(thingName=name)