diff --git a/docs/expectation.rst b/docs/expectation.rst
index 76aeb49c0dc985..6a0c77684a3b83 100644
--- a/docs/expectation.rst
+++ b/docs/expectation.rst
@@ -203,6 +203,10 @@ When used for expectation data, manifests have the following format:
    the (sub)test is disabled and should either not be run (for tests)
    or that its results should be ignored (subtests).
 
+ * A key ``restart-after`` which can be set to any value to indicate that
+   the runner should restart the browser after running this test (e.g. to
+   clear out unwanted state).
+
  * Variables ``debug``, ``os``, ``version``, ``processor`` and
    ``bits`` that describe the configuration of the browser under
    test. ``debug`` is a boolean indicating whether a build is a debug
diff --git a/wptrunner/manifestexpected.py b/wptrunner/manifestexpected.py
index b46a1ef9597574..c0e22a843fdfeb 100644
--- a/wptrunner/manifestexpected.py
+++ b/wptrunner/manifestexpected.py
@@ -29,10 +29,10 @@ def data_cls_getter(output_node, visited_node):
     raise ValueError
 
 
-def disabled(node):
-    """Boolean indicating whether the test is disabled"""
+def bool_prop(name, node):
+    """Boolean property"""
     try:
-        return node.get("disabled")
+        return node.get(name)
     except KeyError:
         return None
 
@@ -109,7 +109,11 @@ def url(self):
 
     @property
     def disabled(self):
-        return disabled(self)
+        return bool_prop("disabled", self)
+
+    @property
+    def restart_after(self):
+        return bool_prop("restart-after", self)
 
     @property
     def tags(self):
@@ -123,7 +127,11 @@ def prefs(self):
 class DirectoryManifest(ManifestItem):
     @property
     def disabled(self):
-        return disabled(self)
+        return bool_prop("disabled", self)
+
+    @property
+    def restart_after(self):
+        return bool_prop("restart-after", self)
 
     @property
     def tags(self):
@@ -164,7 +172,11 @@ def id(self):
 
     @property
     def disabled(self):
-        return disabled(self)
+        return bool_prop("disabled", self)
+
+    @property
+    def restart_after(self):
+        return bool_prop("restart-after", self)
 
     @property
     def tags(self):
diff --git a/wptrunner/testrunner.py b/wptrunner/testrunner.py
index b5617827a40125..77d2a88508347e 100644
--- a/wptrunner/testrunner.py
+++ b/wptrunner/testrunner.py
@@ -524,7 +524,8 @@ def test_ended(self, test, results):
 
         self.test = None
 
-        restart_before_next = (file_result.status in ("CRASH", "EXTERNAL-TIMEOUT") or
+        restart_before_next = (test.restart_after or
+                               file_result.status in ("CRASH", "EXTERNAL-TIMEOUT") or
                                subtest_unexpected or is_unexpected)
 
         if (self.pause_after_test or
diff --git a/wptrunner/wpttest.py b/wptrunner/wpttest.py
index f721f86aecc3f2..9832f72654ea8e 100644
--- a/wptrunner/wpttest.py
+++ b/wptrunner/wpttest.py
@@ -166,6 +166,14 @@ def disabled(self, subtest=None):
                 return disabled
         return None
 
+    @property
+    def restart_after(self):
+        for meta in self.itermeta(None):
+            restart_after = meta.restart_after
+            if restart_after is not None:
+                return True
+        return False
+
     @property
     def tags(self):
         tags = set()