diff --git a/config/config.mk b/config/config.mk
index 6f65244ac6d5..62f8e30d260d 100644
--- a/config/config.mk
+++ b/config/config.mk
@@ -818,4 +818,8 @@ DEFINES += -DNO_NSPR_10_SUPPORT
 #
 #   libs::
 #       $(call py_action,purge_manifests,_build_manifests/purge/foo.manifest)
+ifdef .PYMAKE
+py_action = %mozbuild.action.$(1) main $(2)
+else
 py_action = $(PYTHON) -m mozbuild.action.$(1) $(2)
+endif
diff --git a/js/src/config/config.mk b/js/src/config/config.mk
index 6f65244ac6d5..62f8e30d260d 100644
--- a/js/src/config/config.mk
+++ b/js/src/config/config.mk
@@ -818,4 +818,8 @@ DEFINES += -DNO_NSPR_10_SUPPORT
 #
 #   libs::
 #       $(call py_action,purge_manifests,_build_manifests/purge/foo.manifest)
+ifdef .PYMAKE
+py_action = %mozbuild.action.$(1) main $(2)
+else
 py_action = $(PYTHON) -m mozbuild.action.$(1) $(2)
+endif
diff --git a/python/mozbuild/mozbuild/action/process_install_manifest.py b/python/mozbuild/mozbuild/action/process_install_manifest.py
index 9c5aec14196e..a72c697c1873 100644
--- a/python/mozbuild/mozbuild/action/process_install_manifest.py
+++ b/python/mozbuild/mozbuild/action/process_install_manifest.py
@@ -5,6 +5,7 @@
 from __future__ import print_function, unicode_literals
 
 import argparse
+import sys
 from mozpack.copier import FileCopier
 from mozpack.manifests import InstallManifest
 
@@ -23,7 +24,7 @@ def process_manifest(destdir, paths, remove_unaccounted=True):
     return copier.copy(destdir, remove_unaccounted=remove_unaccounted)
 
 
-if __name__ == '__main__':
+def main(argv):
     parser = argparse.ArgumentParser(
         description='Process install manifest files.')
 
@@ -32,7 +33,7 @@ if __name__ == '__main__':
     parser.add_argument('--no-remove', action='store_true',
         help='Do not remove unaccounted files from destination.')
 
-    args = parser.parse_args()
+    args = parser.parse_args(argv)
 
     result = process_manifest(args.destdir, args.manifests,
         remove_unaccounted=not args.no_remove)
@@ -42,3 +43,6 @@ if __name__ == '__main__':
         updated=result.updated_files_count,
         rm_files=result.removed_files_count,
         rm_dirs=result.removed_directories_count))
+
+if __name__ == '__main__':
+    main(sys.argv[1:])
diff --git a/python/mozbuild/mozbuild/action/xpccheck.py b/python/mozbuild/mozbuild/action/xpccheck.py
index 7183439824ef..ed9ee0a3524e 100644
--- a/python/mozbuild/mozbuild/action/xpccheck.py
+++ b/python/mozbuild/mozbuild/action/xpccheck.py
@@ -61,13 +61,13 @@ def verifyIniFile(initests, directory):
       print >>sys.stderr, "TEST-UNEXPECTED-FAIL | xpccheck | found %s in xpcshell.ini and not in directory '%s'" % (name, directory)
       sys.exit(1)
 
-if __name__ == '__main__':
-  if len(sys.argv) < 3:
+def main(argv):
+  if len(argv) < 2:
     print >>sys.stderr, "Usage: xpccheck.py <topsrcdir> <directory> [<directory> ...]"
     sys.exit(1)
 
-  topsrcdir = sys.argv[1]
-  for d in sys.argv[2:]:
+  topsrcdir = argv[0]
+  for d in argv[1:]:
     # xpcshell-unpack is a copy of xpcshell sibling directory and in the Makefile
     # we copy all files (including xpcshell.ini from the sibling directory.
     if d.endswith('toolkit/mozapps/extensions/test/xpcshell-unpack'):
@@ -76,3 +76,6 @@ if __name__ == '__main__':
     initests = getIniTests(d)
     verifyDirectory(initests, d)
     verifyIniFile(initests, d)
+
+if __name__ == '__main__':
+    main(sys.argv[1:])
diff --git a/python/mozbuild/mozbuild/action/xpidl-process.py b/python/mozbuild/mozbuild/action/xpidl-process.py
index 2396f34bfa90..2cf7d986dbca 100755
--- a/python/mozbuild/mozbuild/action/xpidl-process.py
+++ b/python/mozbuild/mozbuild/action/xpidl-process.py
@@ -65,7 +65,7 @@ def process(input_dir, cache_dir, header_dir, xpt_dir, deps_dir, module, stems):
         mk.dump(fh)
 
 
-if __name__ == '__main__':
+def main(argv):
     parser = argparse.ArgumentParser()
     parser.add_argument('--cache-dir',
         help='Directory in which to find or write cached lexer data.')
@@ -82,6 +82,9 @@ if __name__ == '__main__':
     parser.add_argument('idls', nargs='+',
         help='Source .idl file(s). Specified as stems only.')
 
-    args = parser.parse_args()
+    args = parser.parse_args(argv)
     process(args.inputdir, args.cache_dir, args.headerdir, args.xptdir,
         args.depsdir, args.module, args.idls)
+
+if __name__ == '__main__':
+    main(sys.argv[1:])