diff --git a/Lib/pyclbr.py b/Lib/pyclbr.py
index 97f74f1..b8f71ae 100644
--- a/Lib/pyclbr.py
+++ b/Lib/pyclbr.py
@@ -128,6 +128,8 @@
         parent = _readmodule(package, path, inpackage)
         if inpackage is not None:
             package = "%s.%s" % (inpackage, package)
+        if not '__path__' in parent:
+            raise ImportError('No package named {}'.format(package))
         return _readmodule(submodule, parent['__path__'], package)
 
     # Search the path for the module