--- a/taskcluster/taskgraph/transforms/job/mozharness.py
+++ b/taskcluster/taskgraph/transforms/job/mozharness.py
@@ -78,26 +78,33 @@ mozharness_run_schema = Schema({
     # If false, indicate that builds should skip producing artifacts.  Not
     # supported on Windows.
     Required('keep-artifacts', default=True): bool,
 
     # If specified, use the in-tree job script specified.
     Optional('job-script'): basestring,
 
     Required('requires-signed-builds', default=False): bool,
+
+    # If false, don't set MOZ_SIMPLE_PACKAGE_NAME
+    Required('use-simple-package', default=True): bool,
 })
 
 
 @run_job_using("docker-worker", "mozharness", schema=mozharness_run_schema)
 def mozharness_on_docker_worker_setup(config, job, taskdesc):
     run = job['run']
 
     worker = taskdesc['worker']
     worker['implementation'] = job['worker']['implementation']
 
+    if not run['use-simple-package']:
+        raise NotImplementedError("Simple packaging cannot be disabled via"
+                                  "'use-simple-package' on docker-workers")
+
     # running via mozharness assumes desktop-build (which contains build.sh)
     taskdesc['worker']['docker-image'] = {"in-tree": "desktop-build"}
 
     worker['relengapi-proxy'] = False  # but maybe enabled for tooltool below
     worker['taskcluster-proxy'] = run.get('taskcluster-proxy')
 
     docker_worker_add_public_artifacts(config, job, taskdesc)
     docker_worker_add_workspace_cache(config, job, taskdesc,
@@ -203,19 +210,20 @@ def mozharness_on_generic_worker(config,
     }]
 
     docker_worker_add_gecko_vcs_env_vars(config, job, taskdesc)
 
     env = worker['env']
     env.update({
         'MOZ_BUILD_DATE': config.params['moz_build_date'],
         'MOZ_SCM_LEVEL': config.params['level'],
-        'MOZ_SIMPLE_PACKAGE_NAME': 'target',
         'MOZ_AUTOMATION': '1',
     })
+    if run['use-simple-package']:
+        env.update({'MOZ_SIMPLE_PACKAGE_NAME': 'target'})
 
     if not job['attributes']['build_platform'].startswith('win'):
         raise Exception(
             "Task generation for mozharness build jobs currently only supported on Windows"
         )
 
     mh_command = [r'c:\mozilla-build\python\python.exe']
     mh_command.append('\\'.join([r'.\build\src\testing', run['script'].replace('/', '\\')]))