diff --git a/platformio/managers/core.py b/platformio/managers/core.py
index ba2294ca..7240100d 100644
--- a/platformio/managers/core.py
+++ b/platformio/managers/core.py
@@ -99,10 +99,11 @@ def pioplus_call(args, **kwargs):
 
     pioplus_path = join(get_core_package_dir("tool-pioplus"), "pioplus")
     pythonexe_path = util.get_pythonexe_path()
-    os.environ['PATH'] = (os.pathsep).join(
-        [dirname(pythonexe_path), os.environ['PATH']])
     os.environ['PYTHONEXEPATH'] = pythonexe_path
     os.environ['PYTHONPYSITEDIR'] = get_core_package_dir("pysite-pioplus")
+    os.environ['PYTHONPATH'] = (os.pathsep).join(sys.path)
+    os.environ['PATH'] = (os.pathsep).join(
+        [dirname(pythonexe_path), os.environ['PATH']])
     util.copy_pythonpath_to_osenv()
     code = subprocess.call([pioplus_path] + args, **kwargs)