--- a/testing/marionette/client/marionette_driver/marionette.py
+++ b/testing/marionette/client/marionette_driver/marionette.py
@@ -1701,17 +1701,17 @@ class Marionette(object):
             marionette.execute_script("global.test1 = 'foo';")
             result = self.marionette.execute_script("return global.test1;", new_sandbox=False)
             assert result == "foo"
 
         """
         args = self._to_json(script_args)
         stack = traceback.extract_stack()
         frame = stack[-2:-1][0]  # grab the second-to-last frame
-        body = {"script": script,
+        body = {"script": script.strip(),
                 "args": args,
                 "newSandbox": new_sandbox,
                 "sandbox": sandbox,
                 "scriptTimeout": script_timeout,
                 "line": int(frame[1]),
                 "filename": os.path.basename(frame[0])}
 
         rv = self._send_message("WebDriver:ExecuteScript",
@@ -1751,17 +1751,17 @@ class Marionette(object):
                 marionetteScriptFinished(1);
               }, 5000);
             ''')
             assert result == 1
         """
         args = self._to_json(script_args)
         stack = traceback.extract_stack()
         frame = stack[-2:-1][0]  # grab the second-to-last frame
-        body = {"script": script,
+        body = {"script": script.strip(),
                 "args": args,
                 "newSandbox": new_sandbox,
                 "sandbox": sandbox,
                 "scriptTimeout": script_timeout,
                 "line": int(frame[1]),
                 "filename": os.path.basename(frame[0]),
                 "debug_script": debug_script}