diff --git a/tools/exekall/exekall/_utils.py b/tools/exekall/exekall/_utils.py
index 6b934c2b590ce2d72c278402768db4195ee26cd0..0165337be96a21ad4e4ee0f97dfd4aabc56c3ca3 100644
--- a/tools/exekall/exekall/_utils.py
+++ b/tools/exekall/exekall/_utils.py
@@ -924,6 +924,23 @@ def get_subclasses(cls):
     return subcls_set
 
 
+def get_package(module):
+    """
+    Find the package name of a module. If the module has no package, its own
+    name is taken.
+    """
+    # We keep the search local to the packages these modules are defined in, to
+    # avoid getting a huge set of uninteresting callables.
+    package = module.__package__
+    if package:
+        name = package.split('.', 1)[0]
+    else:
+        name = None
+    # Standalone modules that are not inside a package will get "" as
+    # package name
+    return name or module.__name__
+
+
 def get_recursive_module_set(module_set, package_set, visited_module_set=None):
     """
     Retrieve the set of all modules recursively imported from the modules in
@@ -938,7 +955,7 @@ def get_recursive_module_set(module_set, package_set, visited_module_set=None):
         return any(
             # Either a submodule of one of the packages or one of the
             # packages themselves
-            module.__name__.split('.', 1)[0] == package
+            get_package(module) == package
             for package in package_set
         )
 
diff --git a/tools/exekall/exekall/utils.py b/tools/exekall/exekall/utils.py
index 369961ed5ae968be2a336735d674a916f2f62634..efd940d5b32363c02a7654f20305070ceb6abde1 100644
--- a/tools/exekall/exekall/utils.py
+++ b/tools/exekall/exekall/utils.py
@@ -37,11 +37,8 @@ def get_callable_set(module_set, verbose=False):
     :param module_set: Set of modules to scan.
     :type module_set: set(types.ModuleType)
     """
-    # We keep the search local to the packages these modules are defined in, to
-    # avoid getting a huge set of uninteresting callables.
-    package_set = {
-        module.__package__.split('.', 1)[0] for module in module_set
-    }
+
+    package_set = set(map(get_package, module_set))
     callable_set = set()
     visited_obj_set = set()
     visited_module_set = set()