diff --git a/lib/ansible/constants.py b/lib/ansible/constants.py
index 117b9a1e91a..7bd75777f27 100644
--- a/lib/ansible/constants.py
+++ b/lib/ansible/constants.py
@@ -94,12 +94,12 @@ DEFAULT_KEEP_REMOTE_FILES = get_config(p, DEFAULTS, 'keep_remote_files', 'ANSIBL
 DEFAULT_SUDO_EXE          = get_config(p, DEFAULTS, 'sudo_exe', 'ANSIBLE_SUDO_EXE', 'sudo')
 DEFAULT_HASH_BEHAVIOUR    = get_config(p, DEFAULTS, 'hash_behaviour', 'ANSIBLE_HASH_BEHAVIOUR', 'replace')
 
-DEFAULT_ACTION_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'action_plugins',     None, '/usr/share/ansible_plugins/action_plugins'))
-DEFAULT_CALLBACK_PLUGIN_PATH   = shell_expand_path(get_config(p, DEFAULTS, 'callback_plugins',   None, '/usr/share/ansible_plugins/callback_plugins'))
-DEFAULT_CONNECTION_PLUGIN_PATH = shell_expand_path(get_config(p, DEFAULTS, 'connection_plugins', None, '/usr/share/ansible_plugins/connection_plugins'))
-DEFAULT_LOOKUP_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'lookup_plugins',     None, '/usr/share/ansible_plugins/lookup_plugins'))
-DEFAULT_VARS_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'vars_plugins',     None, '/usr/share/ansible_plugins/vars_plugins'))
-DEFAULT_FILTER_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'filter_plugins',     None, '/usr/share/ansible_plugins/filter_plugins'))
+DEFAULT_ACTION_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'action_plugins',     'ANSIBLE_ACTION_PLUGINS', '/usr/share/ansible_plugins/action_plugins'))
+DEFAULT_CALLBACK_PLUGIN_PATH   = shell_expand_path(get_config(p, DEFAULTS, 'callback_plugins',   'ANSIBLE_CALLBACK_PLUGINS', '/usr/share/ansible_plugins/callback_plugins'))
+DEFAULT_CONNECTION_PLUGIN_PATH = shell_expand_path(get_config(p, DEFAULTS, 'connection_plugins', 'ANSIBLE_CONNECTION_PLUGINS', '/usr/share/ansible_plugins/connection_plugins'))
+DEFAULT_LOOKUP_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'lookup_plugins',     'ANSIBLE_LOOKUP_PLUGINS', '/usr/share/ansible_plugins/lookup_plugins'))
+DEFAULT_VARS_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'vars_plugins',     'ANSIBLE_VARS_PLUGINS', '/usr/share/ansible_plugins/vars_plugins'))
+DEFAULT_FILTER_PLUGIN_PATH     = shell_expand_path(get_config(p, DEFAULTS, 'filter_plugins',     'ANSIBLE_FILTER_PLUGINS', '/usr/share/ansible_plugins/filter_plugins'))
 
 # non-configurable things
 DEFAULT_SUDO_PASS         = None