--- a/python/mozbuild/mozbuild/mach_commands.py
+++ b/python/mozbuild/mozbuild/mach_commands.py
@@ -1092,18 +1092,16 @@ class MachDebug(MachCommandBase):
     def _environment_client_mk(self, out, verbose):
         if self.mozconfig['make_extra']:
             for arg in self.mozconfig['make_extra']:
                 print(arg, file=out)
         if self.mozconfig['make_flags']:
             print('MOZ_MAKE_FLAGS=%s' % ' '.join(self.mozconfig['make_flags']))
         objdir = mozpath.normsep(self.topobjdir)
         print('MOZ_OBJDIR=%s' % objdir, file=out)
-        if 'MOZ_CURRENT_PROJECT' in os.environ:
-            objdir = mozpath.join(objdir, os.environ['MOZ_CURRENT_PROJECT'])
         print('OBJDIR=%s' % objdir, file=out)
         if self.mozconfig['path']:
             print('FOUND_MOZCONFIG=%s' % mozpath.normsep(self.mozconfig['path']),
                 file=out)
 
     def _environment_json(self, out, verbose):
         import json
         class EnvironmentEncoder(json.JSONEncoder):

--- a/python/mozbuild/mozbuild/test/test_base.py
+++ b/python/mozbuild/mozbuild/test/test_base.py
@@ -37,17 +37,16 @@ log_manager = LoggingManager()
 
 
 class TestMozbuildObject(unittest.TestCase):
     def setUp(self):
         self._old_cwd = os.getcwd()
         self._old_env = dict(os.environ)
         os.environ.pop('MOZCONFIG', None)
         os.environ.pop('MOZ_OBJDIR', None)
-        os.environ.pop('MOZ_CURRENT_PROJECT', None)
 
     def tearDown(self):
         os.chdir(self._old_cwd)
         os.environ.clear()
         os.environ.update(self._old_env)
 
     def get_base(self, topobjdir=None):
         return MozbuildObject(topsrcdir, None, log_manager, topobjdir=topobjdir)