diff --git a/CHANGES b/CHANGES
index a90602d9d..1319812cf 100644
--- a/CHANGES
+++ b/CHANGES
@@ -44,6 +44,7 @@ Deprecated
 * ``sphinx.environment.NoUri``
 * ``sphinx.ext.apidoc.format_directive()``
 * ``sphinx.ext.apidoc.format_heading()``
+* ``sphinx.ext.apidoc.makename()``
 * ``sphinx.ext.autodoc.importer.MockFinder``
 * ``sphinx.ext.autodoc.importer.MockLoader``
 * ``sphinx.ext.autodoc.importer.mock()``
diff --git a/doc/extdev/deprecated.rst b/doc/extdev/deprecated.rst
index 2ecb1e2e7..569e0a3d9 100644
--- a/doc/extdev/deprecated.rst
+++ b/doc/extdev/deprecated.rst
@@ -171,6 +171,11 @@ The following is a list of deprecated interfaces.
      - 4.0
      - N/A
 
+   * - ``sphinx.ext.apidoc.makename()``
+     - 2.1
+     - 4.0
+     - ``sphinx.ext.apidoc.module_join()``
+
    * - ``sphinx.ext.autodoc.importer.MockFinder``
      - 2.1
      - 4.0
diff --git a/sphinx/ext/apidoc.py b/sphinx/ext/apidoc.py
index 2243e0644..2ec337d4c 100644
--- a/sphinx/ext/apidoc.py
+++ b/sphinx/ext/apidoc.py
@@ -56,6 +56,8 @@ template_dir = path.join(package_dir, 'templates', 'apidoc')
 def makename(package, module):
     # type: (str, str) -> str
     """Join package and module with a dot."""
+    warnings.warn('makename() is deprecated.',
+                  RemovedInSphinx40Warning)
     # Both package and module can be None/empty.
     if package:
         name = package
@@ -66,6 +68,12 @@ def makename(package, module):
     return name
 
 
+def module_join(*modnames):
+    # type: (*str) -> str
+    """Join module names with dots."""
+    return '.'.join(filter(None, modnames))
+
+
 def write_file(name, text, opts):
     # type: (str, str, Any) -> None
     """Write the output file for module/package <name>."""
@@ -97,7 +105,7 @@ def format_directive(module, package=None):
     """Create the automodule directive and add the options."""
     warnings.warn('format_directive() is deprecated.',
                   RemovedInSphinx40Warning)
-    directive = '.. automodule:: %s\n' % makename(package, module)
+    directive = '.. automodule:: %s\n' % module_join(package, module)
     for option in OPTIONS:
         directive += '    :%s:\n' % option
     return directive
@@ -106,7 +114,7 @@ def format_directive(module, package=None):
 def create_module_file(package, basename, opts):
     # type: (str, str, Any) -> None
     """Build the text of the file and write the file."""
-    qualname = makename(package, basename)
+    qualname = module_join(package, basename)
     context = {
         'show_headings': not opts.noheadings,
         'basename': basename,
@@ -123,17 +131,18 @@ def create_package_file(root, master_package, subroot, py_files, opts, subs, is_
     # build a list of sub packages (directories containing an INITPY file)
     subpackages = [sub for sub in subs if not
                    shall_skip(path.join(root, sub, INITPY), opts, excludes)]
-    subpackages = [makename(makename(master_package, subroot), pkgname)
+    subpackages = [module_join(master_package, subroot, pkgname)
                    for pkgname in subpackages]
     # build a list of sub modules
     submodules = [path.splitext(sub)[0] for sub in py_files
                   if not shall_skip(path.join(root, sub), opts, excludes) and
                   sub != INITPY]
-    submodules = [makename(master_package, makename(subroot, modname))
+    submodules = [module_join(master_package, subroot, modname)
                   for modname in submodules]
 
+    pkgname = module_join(master_package, subroot)
     context = {
-        'pkgname': makename(master_package, subroot),
+        'pkgname': pkgname,
         'subpackages': subpackages,
         'submodules': submodules,
         'is_namespace': is_namespace,
@@ -143,7 +152,7 @@ def create_package_file(root, master_package, subroot, py_files, opts, subs, is_
         'show_headings': not opts.noheadings,
     }
     text = ReSTRenderer(template_dir).render('package.rst', context)
-    write_file(makename(master_package, subroot), text, opts)
+    write_file(pkgname, text, opts)
 
     if submodules and opts.separatemodules:
         for submodule in submodules:
@@ -250,7 +259,7 @@ def recurse_tree(rootpath, excludes, opts):
                 if not is_namespace or len(py_files) > 0:
                     create_package_file(root, root_package, subpackage,
                                         py_files, opts, subs, is_namespace, excludes)
-                    toplevels.append(makename(root_package, subpackage))
+                    toplevels.append(module_join(root_package, subpackage))
         else:
             # if we are at the root level, we don't require it to be a package
             assert root == rootpath and root_package is None