diff --git a/tractor/_exceptions.py b/tractor/_exceptions.py
index 7096912..0466a73 100644
--- a/tractor/_exceptions.py
+++ b/tractor/_exceptions.py
@@ -39,7 +39,7 @@ class NoResult(RuntimeError):
     "No final result is expected for this actor"
 
 
-class ModuleNotExposed(RuntimeError):
+class ModuleNotExposed(ModuleNotFoundError):
     "The requested module is not exposed for RPC"