diff --git a/tiktoken/registry.py b/tiktoken/registry.py
index 52d8ec2d..241747c2 100644
--- a/tiktoken/registry.py
+++ b/tiktoken/registry.py
@@ -27,8 +27,9 @@ def _find_constructors() -> None:
         # - it's a separate top-level package because namespace subpackages of non-namespace
         #   packages don't quite do what you want with editable installs
         plugin_mods = pkgutil.iter_modules(tiktoken_ext.__path__, tiktoken_ext.__name__ + ".")
-
-        for _, mod_name, _ in plugin_mods:
+        filtered_plugin_mods = [(loader, mod_name, ispkg) for loader, mod_name, ispkg in plugin_mods if not mod_name.endswith('__pycache__')]
+        
+        for _, mod_name, _ in filtered_plugin_mods:
             mod = importlib.import_module(mod_name)
             try:
                 constructors = mod.ENCODING_CONSTRUCTORS