diff --git a/ipykernel/debugger.py b/ipykernel/debugger.py
index 24fe92849..b7dd4a259 100644
--- a/ipykernel/debugger.py
+++ b/ipykernel/debugger.py
@@ -693,7 +693,7 @@ async def copyToGlobals(self, message):
 
     async def modules(self, message):
         """Handle a modules message."""
-        modules = list(sys.modules.values())
+        modules = list(sys.modules.copy().values())
         startModule = message.get("startModule", 0)
         moduleCount = message.get("moduleCount", len(modules))
         mods = []
diff --git a/ipykernel/ipkernel.py b/ipykernel/ipkernel.py
index eba728335..95af43e5e 100644
--- a/ipykernel/ipkernel.py
+++ b/ipykernel/ipkernel.py
@@ -120,7 +120,7 @@ def __init__(self, **kwargs):
         from .debugger import _is_debugpy_available
 
         self._kernel_modules = [
-            m.__file__ for m in sys.modules.values() if hasattr(m, "__file__") and m.__file__
+            m.__file__ for m in sys.modules.copy().values() if hasattr(m, "__file__") and m.__file__
         ]
 
         # Initialize the Debugger