diff --git a/lib/legacy/class.html b/lib/legacy/class.html
index cf22f43b53..e61e9e51dd 100644
--- a/lib/legacy/class.html
+++ b/lib/legacy/class.html
@@ -351,6 +351,15 @@
         Polymer.LegacyElementMixin(HTMLElement));
       // decorate klass with registration info
       klass.is = info.is;
+      // To match 1.x behavior, `_template` supplied on a behavior should take
+      // precedence over dom-module lookup for `is`; this also prevents
+      // dom-module injection under strictTemplatePolicy for an element that
+      // would normally get its template from a behavior.
+      // TODO(sorvell): Remove once "flattened behaviors" lands, since both
+      // `_template` and `is` will be on the same class after that change
+      if (klass.prototype._template !== undefined) {
+        klass.prototype._template = klass.prototype._template;
+      }
       return klass;
     };
 
diff --git a/test/unit/behaviors.html b/test/unit/behaviors.html
index 3a9c915f50..98cf74dd7d 100644
--- a/test/unit/behaviors.html
+++ b/test/unit/behaviors.html
@@ -602,8 +602,8 @@
 
   test('template from base', function() {
     var el = fixture('from-base');
-    assert.ok(el.shadowRoot.querySelector('#from-base'));
-    assert.notOk(el.shadowRoot.querySelector('#from-behavior1'));
+    assert.notOk(el.shadowRoot.querySelector('#from-base'));
+    assert.ok(el.shadowRoot.querySelector('#from-behavior1'));
   });
 
   test('template from behavior', function() {