diff --git a/README.rst b/README.rst
index 8891ae2..9432886 100644
--- a/README.rst
+++ b/README.rst
@@ -95,6 +95,8 @@ Usage
       After the first ``--``, all other subsequent arguments will be passed to
       tempest run as is. This is mainly used for quick verification of the
       target test cases. (e.g. ``-- --regex tempest.api.identity.v2.test_token``)
+   g. If you have provisioned multiple user/project accounts you can run parallel
+      test execution by enabling the ``--parallel`` flag.
 
    Use ``refstack-client test --help`` for the full list of arguments.
 
diff --git a/refstack_client/refstack_client.py b/refstack_client/refstack_client.py
index 4fdf0b4..0ebfcc0 100755
--- a/refstack_client/refstack_client.py
+++ b/refstack_client/refstack_client.py
@@ -423,9 +423,11 @@ class RefstackClient:
 
         # Run the tempest run command, conf file specified at _prep_test method
         # Use virtual environment (wrapper script)
-        # telling it to run the tests serially (--serial).
+        # Run the tests serially if parallel not enabled (--serial).
         wrapper = os.path.join(self.tempest_dir, 'tools', 'with_venv.sh')
-        cmd = [wrapper, 'tempest', 'run', '--serial']
+        cmd = [wrapper, 'tempest', 'run']
+        if not self.args.parallel:
+            cmd.append('--serial')
         # If a test list was specified, have it take precedence.
         if self.args.test_list:
             self.logger.info("Normalizing test list...")
@@ -744,6 +746,13 @@ def parse_cli_args(args=None):
                                   'results to the default RefStack API server '
                                   'or the server specified by --url.')
 
+    parser_test.add_argument('-p', '--parallel',
+                             action='store_true',
+                             required=False,
+                             help='Run the tests in parallel. Note this '
+                                  'requires multiple users/projects in '
+                                  'accounts.yaml.')
+
     # This positional argument will allow arbitrary arguments to be passed in
     # with the usage of '--'.
     parser_test.add_argument('arbitrary_args',