diff --git a/TODO b/TODO
index 9acda2186..6919de7ba 100644
--- a/TODO
+++ b/TODO
@@ -24,7 +24,6 @@ decorators for often-used signals from singletons?
     - @on_config_changed('colors')
     - @on_enter_mode('hints')
 find better names for *Parser/*Manager
-Use _foo.py for modules only used in subpackage?
 Use py3.4 Enums with a backport to qutebrowser.utils?
 Simplify using of modes (e.g. enter_mode hint instead of :hint)
 
diff --git a/qutebrowser/app.py b/qutebrowser/app.py
index 7772ddd00..29c387cb8 100644
--- a/qutebrowser/app.py
+++ b/qutebrowser/app.py
@@ -63,7 +63,6 @@ from qutebrowser.commands.parsers import CommandParser, SearchParser
 from qutebrowser.utils.appdirs import AppDirs
 from qutebrowser.utils.misc import dotted_getattr
 from qutebrowser.utils.debug import set_trace  # pylint: disable=unused-import
-from qutebrowser.config.conftypes import ValidationError
 
 
 class QuteBrowser(QApplication):
@@ -110,7 +109,7 @@ class QuteBrowser(QApplication):
             confdir = self._args.confdir
         try:
             config.init(confdir)
-        except ValidationError as e:
+        except config.ValidationError as e:
             msgbox = QMessageBox(
                 QMessageBox.Critical,
                 "Error while reading config!",
diff --git a/qutebrowser/commands/command.py b/qutebrowser/commands/_command.py
similarity index 97%
rename from qutebrowser/commands/command.py
rename to qutebrowser/commands/_command.py
index 4872222d6..5fc000852 100644
--- a/qutebrowser/commands/command.py
+++ b/qutebrowser/commands/_command.py
@@ -19,8 +19,8 @@
 
 import logging
 
-from qutebrowser.commands.exceptions import (ArgumentCountError,
-                                             InvalidModeError)
+from qutebrowser.commands._exceptions import (ArgumentCountError,
+                                              InvalidModeError)
 
 from PyQt5.QtCore import pyqtSignal, QObject
 
diff --git a/qutebrowser/commands/exceptions.py b/qutebrowser/commands/_exceptions.py
similarity index 100%
rename from qutebrowser/commands/exceptions.py
rename to qutebrowser/commands/_exceptions.py
diff --git a/qutebrowser/commands/parsers.py b/qutebrowser/commands/parsers.py
index 7c0712dee..b6df8307a 100644
--- a/qutebrowser/commands/parsers.py
+++ b/qutebrowser/commands/parsers.py
@@ -23,7 +23,7 @@ from PyQt5.QtWebKitWidgets import QWebPage
 import qutebrowser.config.config as config
 import qutebrowser.commands.utils as cmdutils
 import qutebrowser.utils.message as message
-from qutebrowser.commands.exceptions import (
+from qutebrowser.commands._exceptions import (
     ArgumentCountError, NoSuchCommandError, InvalidModeError)
 
 
diff --git a/qutebrowser/commands/utils.py b/qutebrowser/commands/utils.py
index 92cedb123..f60d51f3a 100644
--- a/qutebrowser/commands/utils.py
+++ b/qutebrowser/commands/utils.py
@@ -24,7 +24,7 @@ Module attributes:
 import inspect
 from collections import Iterable
 
-from qutebrowser.commands.command import Command
+from qutebrowser.commands._command import Command
 
 cmd_dict = {}
 
diff --git a/qutebrowser/config/conftypes.py b/qutebrowser/config/_conftypes.py
similarity index 100%
rename from qutebrowser/config/conftypes.py
rename to qutebrowser/config/_conftypes.py
diff --git a/qutebrowser/config/iniparsers.py b/qutebrowser/config/_iniparsers.py
similarity index 100%
rename from qutebrowser/config/iniparsers.py
rename to qutebrowser/config/_iniparsers.py
diff --git a/qutebrowser/config/lineparser.py b/qutebrowser/config/_lineparser.py
similarity index 100%
rename from qutebrowser/config/lineparser.py
rename to qutebrowser/config/_lineparser.py
diff --git a/qutebrowser/config/sections.py b/qutebrowser/config/_sections.py
similarity index 99%
rename from qutebrowser/config/sections.py
rename to qutebrowser/config/_sections.py
index e109a5272..84728a6ab 100644
--- a/qutebrowser/config/sections.py
+++ b/qutebrowser/config/_sections.py
@@ -19,7 +19,7 @@
 
 from collections import OrderedDict, ChainMap
 
-from qutebrowser.config.value import SettingValue
+from qutebrowser.config._value import SettingValue
 
 
 class Section:
diff --git a/qutebrowser/config/value.py b/qutebrowser/config/_value.py
similarity index 100%
rename from qutebrowser/config/value.py
rename to qutebrowser/config/_value.py
diff --git a/qutebrowser/config/config.py b/qutebrowser/config/config.py
index 8116c593e..d8617d05b 100644
--- a/qutebrowser/config/config.py
+++ b/qutebrowser/config/config.py
@@ -40,10 +40,10 @@ from PyQt5.QtCore import pyqtSignal, QObject
 import qutebrowser.config.configdata as configdata
 import qutebrowser.commands.utils as cmdutils
 import qutebrowser.utils.message as message
-from qutebrowser.config.conftypes import ValidationError
-from qutebrowser.config.iniparsers import (ReadConfigParser,
-                                           ReadWriteConfigParser)
-from qutebrowser.config.lineparser import LineConfigParser
+from qutebrowser.config._conftypes import ValidationError
+from qutebrowser.config._iniparsers import (ReadConfigParser,
+                                            ReadWriteConfigParser)
+from qutebrowser.config._lineparser import LineConfigParser
 
 instance = None
 state = None
diff --git a/qutebrowser/config/configdata.py b/qutebrowser/config/configdata.py
index 5a1790e0a..5df59d716 100644
--- a/qutebrowser/config/configdata.py
+++ b/qutebrowser/config/configdata.py
@@ -26,9 +26,9 @@ DATA: The config defaults, an OrderedDict of sections.
 
 from collections import OrderedDict
 
-from qutebrowser.config.value import SettingValue
-import qutebrowser.config.conftypes as types
-import qutebrowser.config.sections as sect
+from qutebrowser.config._value import SettingValue
+import qutebrowser.config._conftypes as types
+import qutebrowser.config._sections as sect
 
 
 FIRST_COMMENT = """
diff --git a/qutebrowser/network/schemehandler.py b/qutebrowser/network/_schemehandler.py
similarity index 100%
rename from qutebrowser/network/schemehandler.py
rename to qutebrowser/network/_schemehandler.py
diff --git a/qutebrowser/network/qutescheme.py b/qutebrowser/network/qutescheme.py
index 15448772f..ca2795319 100644
--- a/qutebrowser/network/qutescheme.py
+++ b/qutebrowser/network/qutescheme.py
@@ -25,8 +25,8 @@ Module attributes:
 import logging
 import cgi
 
-from qutebrowser.network.schemehandler import (SchemeHandler,
-                                               SpecialNetworkReply)
+from qutebrowser.network._schemehandler import (SchemeHandler,
+                                                SpecialNetworkReply)
 from qutebrowser.utils.version import version
 from qutebrowser.utils.url import urlstring
 
diff --git a/qutebrowser/widgets/completion.py b/qutebrowser/widgets/_completion.py
similarity index 100%
rename from qutebrowser/widgets/completion.py
rename to qutebrowser/widgets/_completion.py
diff --git a/qutebrowser/widgets/statusbar.py b/qutebrowser/widgets/_statusbar.py
similarity index 100%
rename from qutebrowser/widgets/statusbar.py
rename to qutebrowser/widgets/_statusbar.py
diff --git a/qutebrowser/widgets/tabbedbrowser.py b/qutebrowser/widgets/_tabbedbrowser.py
similarity index 99%
rename from qutebrowser/widgets/tabbedbrowser.py
rename to qutebrowser/widgets/_tabbedbrowser.py
index 09860e686..6e216485a 100644
--- a/qutebrowser/widgets/tabbedbrowser.py
+++ b/qutebrowser/widgets/_tabbedbrowser.py
@@ -28,7 +28,7 @@ import qutebrowser.utils.url as urlutils
 import qutebrowser.utils.message as message
 import qutebrowser.config.config as config
 import qutebrowser.commands.utils as cmdutils
-from qutebrowser.widgets.tabwidget import TabWidget
+from qutebrowser.widgets._tabwidget import TabWidget
 from qutebrowser.widgets.browsertab import BrowserTab
 from qutebrowser.browser.signalfilter import SignalFilter
 from qutebrowser.browser.curcommand import CurCommandDispatcher
diff --git a/qutebrowser/widgets/tabwidget.py b/qutebrowser/widgets/_tabwidget.py
similarity index 100%
rename from qutebrowser/widgets/tabwidget.py
rename to qutebrowser/widgets/_tabwidget.py
diff --git a/qutebrowser/widgets/mainwindow.py b/qutebrowser/widgets/mainwindow.py
index b0367a11a..696cc8ba1 100644
--- a/qutebrowser/widgets/mainwindow.py
+++ b/qutebrowser/widgets/mainwindow.py
@@ -24,9 +24,9 @@ from PyQt5.QtCore import pyqtSlot, QRect, QPoint
 from PyQt5.QtWidgets import QWidget, QVBoxLayout
 from PyQt5.QtWebKitWidgets import QWebInspector
 
-from qutebrowser.widgets.statusbar import StatusBar
-from qutebrowser.widgets.tabbedbrowser import TabbedBrowser
-from qutebrowser.widgets.completion import CompletionView
+from qutebrowser.widgets._statusbar import StatusBar
+from qutebrowser.widgets._tabbedbrowser import TabbedBrowser
+from qutebrowser.widgets._completion import CompletionView
 import qutebrowser.commands.utils as cmdutils
 import qutebrowser.config.config as config