diff --git a/pdoc/__init__.py b/pdoc/__init__.py
index 7b6c873e..c02213b1 100644
--- a/pdoc/__init__.py
+++ b/pdoc/__init__.py
@@ -761,6 +761,24 @@ def iter_modules(paths):
                 if m.is_namespace and not m.doc:
                     del self.doc[root]
                     self._context.pop(m.refname)
+        elif hasattr(self.obj, '__all__'):
+            # Python extension modules don't get recognized by `is_package` because they have no
+            # "__path__" attribute. We treat them here separately. We support submodules of
+            # extension modules only if they are explicitly exposed via the "__all__" attribute
+            # because otherwise it's hard to distinguish proper submodules from re-exports (i.e.,
+            # the function  `is_from_this_module` doesn't work on submodules).
+            for name, obj in public_objs:
+                if inspect.ismodule(obj) and not hasattr(obj, '__file__') and name not in self.doc:
+                    try:
+                        m = Module(
+                            obj, docfilter=docfilter, supermodule=self,
+                            context=self._context, skip_errors=skip_errors)
+                    except Exception as ex:
+                        if skip_errors:
+                            warn(str(ex), Module.ImportWarning)
+                            continue
+                        raise
+                    self.doc[name] = m
 
         # Apply docfilter
         if docfilter:
diff --git a/pdoc/test/__init__.py b/pdoc/test/__init__.py
index c967dc87..d95e6191 100644
--- a/pdoc/test/__init__.py
+++ b/pdoc/test/__init__.py
@@ -472,6 +472,35 @@ def test_module(self):
                     self.assertEqual(sorted(m.name for m in m.submodules()),
                                      [EXAMPLE_MODULE + '.' + m for m in submodules])
 
+    @ignore_warnings
+    def test_module_without_path(self):
+        # GH-319: https://github.com/pdoc3/pdoc/issues/319
+        parent_module = ModuleType('parent_module')
+        child_module1 = ModuleType('child_module1')
+        child_module2 = ModuleType('child_module2')
+        grandchild_module = ModuleType('grandchild_module')
+
+        child_module1.grandchild_module = grandchild_module
+        child_module1.__all__ = ['grandchild_module']
+
+        parent_module.child_module1 = child_module1
+        parent_module.child_module2 = child_module2
+        parent_module.__all__ = ['child_module1', 'child_module2']
+
+        assert not hasattr(parent_module, '__path__')
+        assert not hasattr(child_module1, '__path__')
+        assert not hasattr(child_module2, '__path__')
+        assert not hasattr(grandchild_module, '__path__')
+
+        parent_module_pdoc = pdoc.Module(parent_module)
+
+        children_modules_pdoc = sorted(parent_module_pdoc.submodules(), key=lambda m: m.name)
+        self.assertEqual(
+            [m.name for m in children_modules_pdoc], ['child_module1', 'child_module2'])
+        self.assertEqual(
+            [m.name for m in children_modules_pdoc[0].submodules()], ['grandchild_module'])
+        self.assertEqual(children_modules_pdoc[1].submodules(), [])
+
     def test_Module_find_class(self):
         class A:
             pass