diff --git a/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchParser.java b/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchParser.java
index 524913105823a..a825295c7c8a3 100644
--- a/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchParser.java
+++ b/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/watch/WatchParser.java
@@ -5,6 +5,7 @@
  */
 package org.elasticsearch.xpack.watcher.watch;
 
+import com.fasterxml.jackson.core.JsonParseException;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.bytes.BytesReference;
@@ -174,6 +175,14 @@ public Watch parse(String id, boolean includeStatus, WatcherXContentParser parse
                 throw new ElasticsearchParseException("could not parse watch [{}]. unexpected field [{}]", id, currentFieldName);
             }
         }
+
+        // Make sure we are at the end of the available input data -- certain types of JSON errors will not manifest
+        // until we try to consume additional tokens.
+
+        if (parser.nextToken() != null) {
+            throw new ElasticsearchParseException("could not parse watch [{}].  expected end of payload, but received additional " +
+                "data at [line: {}, column: {}]", id, parser.getTokenLocation().lineNumber, parser.getTokenLocation().columnNumber);
+        }
         if (trigger == null) {
             throw new ElasticsearchParseException("could not parse watch [{}]. missing required field [{}]", id,
                     WatchField.TRIGGER.getPreferredName());
diff --git a/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchTests.java b/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchTests.java
index df96a802166e2..09e94ed916505 100644
--- a/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchTests.java
+++ b/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/watch/WatchTests.java
@@ -11,14 +11,18 @@
 import org.elasticsearch.action.support.WriteRequest;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.DeprecationHandler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.common.xcontent.json.JsonXContent;
+import org.elasticsearch.common.xcontent.json.JsonXContentParser;
 import org.elasticsearch.index.query.MatchAllQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.ScriptQueryBuilder;
@@ -121,6 +125,7 @@
 import org.junit.Before;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.time.Clock;
 import java.time.Instant;
 import java.time.ZoneOffset;
@@ -143,6 +148,8 @@
 import static org.elasticsearch.xpack.watcher.input.InputBuilders.searchInput;
 import static org.elasticsearch.xpack.watcher.test.WatcherTestUtils.templateRequest;
 import static org.elasticsearch.xpack.watcher.trigger.TriggerBuilders.schedule;
+
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.instanceOf;
@@ -296,6 +303,47 @@ public void testParserBadActions() throws Exception {
         }
     }
 
+    public void testParserConsumesEntireDefinition() throws Exception {
+        WatchParser wp = createWatchparser();
+        try (XContentBuilder builder = jsonBuilder()) {
+            builder.startObject();
+            {
+                builder.startObject("trigger");
+                {
+                    builder.startObject("schedule");
+                    {
+                        builder.field("interval", "10s");
+                    }
+                    builder.endObject();
+                }
+                builder.endObject();
+                builder.startObject("input");
+                {
+                    builder.startObject("simple");
+                    {
+                    }
+                    builder.endObject();
+                }
+                builder.endObject();
+                builder.startObject("condition");
+                {
+                    builder.startObject("script");
+                    {
+                        builder.field("source", "return false");
+                    }
+                    builder.endObject();
+                }
+                builder.endObject();
+            }
+            builder.endObject();
+            builder.generator().writeBinary(",".getBytes(StandardCharsets.UTF_8));
+            ElasticsearchParseException e = expectThrows(
+                ElasticsearchParseException.class,
+                () -> wp.parseWithSecrets("failure", false, BytesReference.bytes(builder), new DateTime(), XContentType.JSON, true));
+            assertThat(e.getMessage(), containsString("expected end of payload"));
+        }
+    }
+
     public void testParserDefaults() throws Exception {
         Schedule schedule = randomSchedule();
         ScheduleRegistry scheduleRegistry = registry(schedule);