diff --git a/plugin/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchStatus.java b/plugin/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchStatus.java
index c084078bab3..6b17d41319a 100644
--- a/plugin/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchStatus.java
+++ b/plugin/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchStatus.java
@@ -117,6 +117,10 @@ public class WatchStatus implements ToXContentObject, Streamable {
         lastChecked = timestamp;
         if (metCondition) {
             lastMetCondition = timestamp;
+        } else {
+            for (ActionStatus status : actions.values()) {
+                status.resetAckStatus(timestamp);
+            }
         }
     }
 
diff --git a/plugin/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchStatusTests.java b/plugin/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchStatusTests.java
new file mode 100644
index 00000000000..85ad27ddb2a
--- /dev/null
+++ b/plugin/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchStatusTests.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.watcher.watch;
+
+import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.xpack.watcher.actions.ActionStatus;
+import org.elasticsearch.xpack.watcher.actions.ActionStatus.AckStatus.State;
+import org.elasticsearch.xpack.watcher.actions.logging.LoggingAction;
+
+import java.util.HashMap;
+
+import static org.hamcrest.Matchers.is;
+import static org.joda.time.DateTime.now;
+
+public class WatchStatusTests extends ESTestCase {
+
+    public void testAckStatusIsResetOnUnmetCondition() {
+        HashMap<String, ActionStatus> myMap = new HashMap<>();
+        ActionStatus actionStatus = new ActionStatus(now());
+        myMap.put("foo", actionStatus);
+
+        actionStatus.update(now(), new LoggingAction.Result.Success("foo"));
+        actionStatus.onAck(now());
+        assertThat(actionStatus.ackStatus().state(), is(State.ACKED));
+
+        WatchStatus status = new WatchStatus(now(), myMap);
+        status.onCheck(false, now());
+
+        assertThat(status.actionStatus("foo").ackStatus().state(), is(State.AWAITS_SUCCESSFUL_EXECUTION));
+    }
+}
\ No newline at end of file
diff --git a/plugin/src/test/resources/rest-api-spec/test/watcher/ack_watch/30_reset_ack_after_unmet_condition.yaml b/plugin/src/test/resources/rest-api-spec/test/watcher/ack_watch/30_reset_ack_after_unmet_condition.yaml
new file mode 100644
index 00000000000..5479de679a9
--- /dev/null
+++ b/plugin/src/test/resources/rest-api-spec/test/watcher/ack_watch/30_reset_ack_after_unmet_condition.yaml
@@ -0,0 +1,105 @@
+---
+setup:
+  - do:
+      cluster.health:
+          wait_for_status: yellow
+
+---
+teardown:
+  - do:
+      xpack.watcher.delete_watch:
+        id: "my_watch"
+        ignore: 404
+
+# See https://github.com/elastic/x-pack-elasticsearch/issues/1123
+---
+"Ensure that ack status is reset after unsuccesful execution":
+
+  - do:
+      xpack.watcher.put_watch:
+        id: "my_watch"
+        body: >
+          {
+            "trigger": {
+              "schedule": {
+                "interval": "1m"
+              }
+            },
+            "input": {
+              "simple" : { "match" : "true" }
+            },
+            "condition": {
+              "compare": {
+                "ctx.payload.match": {
+                  "eq": "true"
+                }
+              }
+            },
+            "actions": {
+              "indexme" : {
+                "index" : {
+                  "index" : "my-index",
+                  "doc_type" : "my-type",
+                  "doc_id": "my-id"
+                }
+              }
+            }
+          }
+
+  - do:
+      xpack.watcher.execute_watch:
+        id: "my_watch"
+        body: >
+          {
+            "record_execution" : true
+          }
+  - match: { watch_record._status.actions.indexme.ack.state: "ackable" }
+
+  - do:
+      xpack.watcher.ack_watch:
+        watch_id: "my_watch"
+  - match: { "_status.actions.indexme.ack.state" : "acked" }
+
+  - do:
+      xpack.watcher.get_watch:
+        id: "my_watch"
+  - match: { "_status.actions.indexme.ack.state" : "acked" }
+
+  # having a false result will reset the ack state
+  - do:
+      xpack.watcher.execute_watch:
+        id: "my_watch"
+        body: >
+          {
+            "record_execution" : true,
+            "alternative_input" : {
+              "match" : "false"
+            },
+            "action_modes" : {
+              "indexme" : "force_execute"
+            }
+          }
+  - match: { watch_record._status.actions.indexme.ack.state: "awaits_successful_execution" }
+
+  - do:
+      xpack.watcher.get_watch:
+        id: "my_watch"
+  - match: { "_status.actions.indexme.ack.state" : "awaits_successful_execution" }
+
+  - do:
+      xpack.watcher.execute_watch:
+        id: "my_watch"
+        body: >
+          {
+            "record_execution" : true,
+            "action_modes" : {
+              "indexme" : "force_execute"
+            }
+          }
+  - match: { watch_record._status.actions.indexme.ack.state: "ackable" }
+
+  - do:
+      xpack.watcher.get_watch:
+        id: "my_watch"
+  - match: { "_status.actions.indexme.ack.state" : "ackable" }
+