diff --git a/comtypes/hints.pyi b/comtypes/hints.pyi
index 30fb4906..7d7e5689 100644
--- a/comtypes/hints.pyi
+++ b/comtypes/hints.pyi
@@ -23,8 +23,10 @@ else:
     from typing_extensions import Protocol
 if sys.version_info >= (3, 10):
     from typing import Concatenate, ParamSpec, TypeAlias
+    from typing import TypeGuard as TypeGuard
 else:
     from typing_extensions import Concatenate, ParamSpec, TypeAlias
+    from typing_extensions import TypeGuard as TypeGuard
 if sys.version_info >= (3, 11):
     from typing import Self
 else:
diff --git a/comtypes/tools/codegenerator.py b/comtypes/tools/codegenerator.py
index afc14cc7..4dca21e2 100644
--- a/comtypes/tools/codegenerator.py
+++ b/comtypes/tools/codegenerator.py
@@ -421,6 +421,16 @@ def _get_common_elms(self) -> Tuple[List[_IdlFlagType], str, str]:
         return (idlflags, type_name, self._m.name)
 
 
+_InterfaceTypeDesc = _UnionT[
+    typedesc.ComInterface,
+    typedesc.ComInterfaceHead,
+    typedesc.ComInterfaceBody,
+    typedesc.DispInterface,
+    typedesc.DispInterfaceHead,
+    typedesc.DispInterfaceBody,
+]
+
+
 class CodeGenerator(object):
     def __init__(self, known_symbols=None, known_interfaces=None) -> None:
         self.stream = io.StringIO()
@@ -441,13 +451,8 @@ def __init__(self, known_symbols=None, known_interfaces=None) -> None:
     def generate(self, item):
         if item in self.done:
             return
-        if isinstance(item, typedesc.ComInterface):
-            if self._is_known_interface(item):
-                self.imports.add(item.name, symbols=self.known_symbols)
-                self.done.add(item)
-                return
-            self.done.add(item)  # to avoid infinite recursion.
-            self.ComInterface(item)
+        if self._is_interface_typedesc(item):
+            self._define_interface(item)
             return
         if isinstance(item, typedesc.StructureHead):
             name = getattr(item.struct, "name", None)
@@ -1080,12 +1085,56 @@ def CoClass(self, coclass: typedesc.CoClass) -> None:
 
         self.names.add(coclass.name)
 
+    def _is_interface_typedesc(
+        self, item: Any
+    ) -> "comtypes.hints.TypeGuard[_InterfaceTypeDesc]":
+        return isinstance(
+            item,
+            (
+                typedesc.ComInterface,
+                typedesc.ComInterfaceHead,
+                typedesc.ComInterfaceBody,
+                typedesc.DispInterface,
+                typedesc.DispInterfaceHead,
+                typedesc.DispInterfaceBody,
+            ),
+        )
+
+    def _define_interface(self, item: _InterfaceTypeDesc) -> None:
+        if isinstance(
+            item,
+            (
+                typedesc.ComInterfaceHead,
+                typedesc.ComInterfaceBody,
+                typedesc.DispInterfaceHead,
+                typedesc.DispInterfaceBody,
+            ),
+        ):
+            if self._is_known_interface(item.itf):
+                self.imports.add(item.itf.name, symbols=self.known_symbols)
+                self.done.add(item)
+                return
+        elif isinstance(item, (typedesc.ComInterface, typedesc.DispInterface)):
+            if self._is_known_interface(item):
+                self.imports.add(item.name, symbols=self.known_symbols)
+                self.done.add(item)
+                self.done.add(item.get_head())
+                self.done.add(item.get_body())
+                return
+        else:
+            raise TypeError
+        self.done.add(item)  # to avoid infinite recursion.
+        mth = getattr(self, type(item).__name__)
+        mth(item)
+
     def ComInterface(self, itf: typedesc.ComInterface) -> None:
         self.generate(itf.get_head())
         self.generate(itf.get_body())
         self.names.add(itf.name)
 
-    def _is_known_interface(self, item: typedesc.ComInterface) -> bool:
+    def _is_known_interface(
+        self, item: _UnionT[typedesc.ComInterface, typedesc.DispInterface]
+    ) -> bool:
         """Returns whether an interface is statically defined in `comtypes`,
         based on its name and iid.
         """
@@ -1104,14 +1153,11 @@ def _is_enuminterface(self, itf: typedesc.ComInterface) -> bool:
         return True
 
     def ComInterfaceHead(self, head: typedesc.ComInterfaceHead) -> None:
-        if self._is_known_interface(head.itf):
-            return
-        base = head.itf.base
         if head.itf.base is None:
             # we don't beed to generate IUnknown
             return
-        self.generate(base.get_head())
-        self.more.add(base)
+        self.generate(head.itf.base.get_head())
+        self.more.add(head.itf.base)
         basename = self._to_type_name(head.itf.base)
 
         self.imports.add("comtypes", "GUID")
diff --git a/comtypes/tools/typedesc.py b/comtypes/tools/typedesc.py
index 3085f0ea..8bf167cc 100644
--- a/comtypes/tools/typedesc.py
+++ b/comtypes/tools/typedesc.py
@@ -176,7 +176,7 @@ def __init__(
         self,
         name: str,
         members: List[ComMethod],
-        base: Any,
+        base: "Optional[ComInterface]",
         iid: str,
         idlflags: List[str],
     ) -> None: