diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
index 2335b2ef0f171..5f81335e3e1b1 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
@@ -188,8 +188,13 @@ class ScriptedPythonInterface : virtual public ScriptedInterface {
       // This addresses the cases where the embedded interpreter session
       // dictionary is passed to the extension initializer which is not used
       // most of the time.
+      // Note, though none of our API's suggest defining the interfaces with
+      // varargs, we have some extant clients that were doing that.  To keep
+      // from breaking them, we just say putting a varargs in these signatures
+      // turns off argument checking.
       size_t num_args = sizeof...(Args);
-      if (num_args != arg_info->max_positional_args) {
+      if (arg_info->max_positional_args != PythonCallable::ArgInfo::UNBOUNDED &&
+          num_args != arg_info->max_positional_args) {
         if (num_args != arg_info->max_positional_args - 1)
           return create_error("Passed arguments ({0}) doesn't match the number "
                               "of expected arguments ({1}).",