diff --git a/moto/swf/models/history_event.py b/moto/swf/models/history_event.py
index 10e97ecb3..4c7168b06 100644
--- a/moto/swf/models/history_event.py
+++ b/moto/swf/models/history_event.py
@@ -64,6 +64,13 @@ class HistoryEvent(object):
             if hasattr(self, "execution_context") and self.execution_context:
                 hsh["executionContext"] = self.execution_context
             return hsh
+        elif self.event_type == "WorkflowExecutionCompleted":
+            hsh = {
+                "decisionTaskCompletedEventId": self.decision_task_completed_event_id,
+            }
+            if hasattr(self, "result") and self.result:
+                hsh["result"] = self.result
+            return hsh
         else:
             raise NotImplementedError(
                 "HistoryEvent does not implement attributes for type '{}'".format(self.event_type)
diff --git a/moto/swf/models/workflow_execution.py b/moto/swf/models/workflow_execution.py
index bee4305c0..fe35b2fdb 100644
--- a/moto/swf/models/workflow_execution.py
+++ b/moto/swf/models/workflow_execution.py
@@ -162,9 +162,9 @@ class WorkflowExecution(object):
             execution_context=execution_context,
         )
         dt.complete()
-        self.handle_decisions(decisions)
+        self.handle_decisions(evt.event_id, decisions)
 
-    def handle_decisions(self, decisions):
+    def handle_decisions(self, event_id, decisions):
         """
         Handles a Decision according to SWF docs.
         See: http://docs.aws.amazon.com/amazonswf/latest/apireference/API_Decision.html
@@ -176,17 +176,31 @@ class WorkflowExecution(object):
         # handle each decision separately, in order
         for decision in decisions:
             decision_type = decision["decisionType"]
-            # TODO: implement Decision type: CancelTimer
-            # TODO: implement Decision type: CancelWorkflowExecution
-            # TODO: implement Decision type: CompleteWorkflowExecution
-            # TODO: implement Decision type: ContinueAsNewWorkflowExecution
-            # TODO: implement Decision type: FailWorkflowExecution
-            # TODO: implement Decision type: RecordMarker
-            # TODO: implement Decision type: RequestCancelActivityTask
-            # TODO: implement Decision type: RequestCancelExternalWorkflowExecution
-            # TODO: implement Decision type: ScheduleActivityTask
-            # TODO: implement Decision type: ScheduleLambdaFunction
-            # TODO: implement Decision type: SignalExternalWorkflowExecution
-            # TODO: implement Decision type: StartChildWorkflowExecution
-            # TODO: implement Decision type: StartTimer
-            raise NotImplementedError("Cannot handle decision: {}".format(decision_type))
+            attributes_key = "{}{}EventAttributes".format(
+                decision_type[0].lower(), decision_type[1:]
+            )
+            attributes = decision.get(attributes_key, {})
+            if decision_type == "CompleteWorkflowExecution":
+                self.complete(event_id, attributes.get("result"))
+            else:
+                # TODO: implement Decision type: CancelTimer
+                # TODO: implement Decision type: CancelWorkflowExecution
+                # TODO: implement Decision type: ContinueAsNewWorkflowExecution
+                # TODO: implement Decision type: FailWorkflowExecution
+                # TODO: implement Decision type: RecordMarker
+                # TODO: implement Decision type: RequestCancelActivityTask
+                # TODO: implement Decision type: RequestCancelExternalWorkflowExecution
+                # TODO: implement Decision type: ScheduleActivityTask
+                # TODO: implement Decision type: ScheduleLambdaFunction
+                # TODO: implement Decision type: SignalExternalWorkflowExecution
+                # TODO: implement Decision type: StartChildWorkflowExecution
+                # TODO: implement Decision type: StartTimer
+                raise NotImplementedError("Cannot handle decision: {}".format(decision_type))
+
+    def complete(self, event_id, result=None):
+        self.execution_status = "CLOSED"
+        evt = self._add_event(
+            "WorkflowExecutionCompleted",
+            decision_task_completed_event_id=event_id,
+            result=result,
+        )
diff --git a/tests/test_swf/test_decision_tasks.py b/tests/test_swf/test_decision_tasks.py
index fe84f2ebd..9db1a2649 100644
--- a/tests/test_swf/test_decision_tasks.py
+++ b/tests/test_swf/test_decision_tasks.py
@@ -134,3 +134,26 @@ def test_respond_decision_task_completed_with_task_already_completed():
     conn.respond_decision_task_completed.when.called_with(
         task_token
     ).should.throw(SWFUnknownResourceFault)
+
+@mock_swf
+def test_respond_decision_task_completed_with_complete_workflow_execution():
+    conn = setup_workflow()
+    resp = conn.poll_for_decision_task("test-domain", "queue")
+    task_token = resp["taskToken"]
+
+    decisions = [{
+        "decisionType": "CompleteWorkflowExecution",
+        "completeWorkflowExecutionEventAttributes": {}
+    }]
+    resp = conn.respond_decision_task_completed(task_token, decisions=decisions)
+    resp.should.be.none
+
+    resp = conn.get_workflow_execution_history("test-domain", conn.run_id, "uid-abcd1234")
+    types = [evt["eventType"] for evt in resp["events"]]
+    types.should.equal([
+        "WorkflowExecutionStarted",
+        "DecisionTaskScheduled",
+        "DecisionTaskStarted",
+        "DecisionTaskCompleted",
+        "WorkflowExecutionCompleted",
+    ])
diff --git a/tests/test_swf/test_models.py b/tests/test_swf/test_models.py
index 59c6eac59..31dc3a9ad 100644
--- a/tests/test_swf/test_models.py
+++ b/tests/test_swf/test_models.py
@@ -209,6 +209,16 @@ def test_workflow_execution_history_events_ids():
     ids = [evt.event_id for evt in wfe.events()]
     ids.should.equal([1, 2, 3])
 
+def test_workflow_execution_complete():
+    wft = get_basic_workflow_type()
+    wfe = WorkflowExecution(wft, "ab1234")
+    wfe.complete(123, result="foo")
+
+    wfe.execution_status.should.equal("CLOSED")
+    wfe.events()[-1].event_type.should.equal("WorkflowExecutionCompleted")
+    wfe.events()[-1].decision_task_completed_event_id.should.equal(123)
+    wfe.events()[-1].result.should.equal("foo")
+
 
 # HistoryEvent
 @freeze_time("2015-01-01 12:00:00")