diff --git a/src/base/bittorrent/magneturi.cpp b/src/base/bittorrent/magneturi.cpp
index f15ff39d0..cff9bb6cf 100644
--- a/src/base/bittorrent/magneturi.cpp
+++ b/src/base/bittorrent/magneturi.cpp
@@ -34,6 +34,7 @@
 #include <libtorrent/sha1_hash.hpp>
 
 #include <QRegularExpression>
+#include <QUrl>
 
 #include "infohash.h"
 
diff --git a/src/base/bittorrent/magneturi.h b/src/base/bittorrent/magneturi.h
index e2b8757c3..f82dfc8d6 100644
--- a/src/base/bittorrent/magneturi.h
+++ b/src/base/bittorrent/magneturi.h
@@ -29,15 +29,16 @@
 #ifndef BITTORRENT_MAGNETURI_H
 #define BITTORRENT_MAGNETURI_H
 
+#include <libtorrent/add_torrent_params.hpp>
+
 #include <QList>
 #include <QString>
-#include <QUrl>
-
-#include <libtorrent/add_torrent_params.hpp>
 
 #include "infohash.h"
 #include "trackerentry.h"
 
+class QUrl;
+
 namespace BitTorrent
 {
     class MagnetUri
diff --git a/src/base/bittorrent/peerinfo.h b/src/base/bittorrent/peerinfo.h
index 6aae66f75..6fb3114af 100644
--- a/src/base/bittorrent/peerinfo.h
+++ b/src/base/bittorrent/peerinfo.h
@@ -29,12 +29,12 @@
 #ifndef BITTORRENT_PEERINFO_H
 #define BITTORRENT_PEERINFO_H
 
+#include <libtorrent/peer_info.hpp>
+
 #include <QBitArray>
 #include <QCoreApplication>
 #include <QHostAddress>
 
-#include <libtorrent/peer_info.hpp>
-
 namespace BitTorrent
 {
     class TorrentHandle;
diff --git a/src/base/bittorrent/private/bandwidthscheduler.cpp b/src/base/bittorrent/private/bandwidthscheduler.cpp
index 308b3217e..a541a2427 100644
--- a/src/base/bittorrent/private/bandwidthscheduler.cpp
+++ b/src/base/bittorrent/private/bandwidthscheduler.cpp
@@ -33,6 +33,7 @@
 
 #include <QDate>
 #include <QTime>
+#include <QTimer>
 
 #include "base/preferences.h"
 
diff --git a/src/base/bittorrent/private/filterparserthread.h b/src/base/bittorrent/private/filterparserthread.h
index 0f374bbf5..7b86aa4f6 100644
--- a/src/base/bittorrent/private/filterparserthread.h
+++ b/src/base/bittorrent/private/filterparserthread.h
@@ -29,10 +29,10 @@
 #ifndef FILTERPARSERTHREAD_H
 #define FILTERPARSERTHREAD_H
 
-#include <QThread>
-
 #include <libtorrent/ip_filter.hpp>
 
+#include <QThread>
+
 class QDataStream;
 
 class FilterParserThread : public QThread
diff --git a/src/base/bittorrent/private/portforwarderimpl.cpp b/src/base/bittorrent/private/portforwarderimpl.cpp
index 23d8d6dbd..1a7eb02bf 100644
--- a/src/base/bittorrent/private/portforwarderimpl.cpp
+++ b/src/base/bittorrent/private/portforwarderimpl.cpp
@@ -28,10 +28,10 @@
 
 #include "portforwarderimpl.h"
 
-#include <QDebug>
-
 #include <libtorrent/session.hpp>
 
+#include <QDebug>
+
 #include "base/logger.h"
 #include "base/settingsstorage.h"
 
diff --git a/src/base/bittorrent/private/resumedatasavingmanager.cpp b/src/base/bittorrent/private/resumedatasavingmanager.cpp
index f9dc7b847..4fd93722d 100644
--- a/src/base/bittorrent/private/resumedatasavingmanager.cpp
+++ b/src/base/bittorrent/private/resumedatasavingmanager.cpp
@@ -28,6 +28,7 @@
 
 #include "resumedatasavingmanager.h"
 
+#include <QByteArray>
 #include <QDebug>
 #include <QSaveFile>
 
diff --git a/src/base/bittorrent/private/resumedatasavingmanager.h b/src/base/bittorrent/private/resumedatasavingmanager.h
index 3f27d94a0..ffef21e91 100644
--- a/src/base/bittorrent/private/resumedatasavingmanager.h
+++ b/src/base/bittorrent/private/resumedatasavingmanager.h
@@ -28,10 +28,11 @@
 
 #pragma once
 
-#include <QByteArray>
 #include <QDir>
 #include <QObject>
 
+class QByteArray;
+
 class ResumeDataSavingManager : public QObject
 {
     Q_OBJECT
diff --git a/src/base/bittorrent/session.h b/src/base/bittorrent/session.h
index d2c91b7e8..65a540414 100644
--- a/src/base/bittorrent/session.h
+++ b/src/base/bittorrent/session.h
@@ -43,7 +43,6 @@
 #include <QSet>
 
 #include "base/settingvalue.h"
-#include "base/tristatebool.h"
 #include "base/types.h"
 #include "addtorrentparams.h"
 #include "cachestatus.h"
diff --git a/src/base/bittorrent/torrentinfo.h b/src/base/bittorrent/torrentinfo.h
index 207736954..f06f64765 100644
--- a/src/base/bittorrent/torrentinfo.h
+++ b/src/base/bittorrent/torrentinfo.h
@@ -29,7 +29,6 @@
 #ifndef BITTORRENT_TORRENTINFO_H
 #define BITTORRENT_TORRENTINFO_H
 
-#include <libtorrent/fwd.hpp>
 #include <libtorrent/torrent_info.hpp>
 #include <libtorrent/version.hpp>
 
diff --git a/src/base/filesystemwatcher.h b/src/base/filesystemwatcher.h
index ac17d7124..af4c96163 100644
--- a/src/base/filesystemwatcher.h
+++ b/src/base/filesystemwatcher.h
@@ -32,9 +32,11 @@
 #include <QDir>
 #include <QFileSystemWatcher>
 #include <QHash>
-#include <QStringList>
+#include <QList>
 #include <QTimer>
 
+class QStringList;
+
 /*
  * Subclassing QFileSystemWatcher in order to support Network File
  * System watching (NFS, CIFS) on Linux and Mac OS.
diff --git a/src/base/iconprovider.h b/src/base/iconprovider.h
index 3bba13361..b6ea47f8c 100644
--- a/src/base/iconprovider.h
+++ b/src/base/iconprovider.h
@@ -31,7 +31,8 @@
 #define ICONPROVIDER_H
 
 #include <QObject>
-#include <QString>
+
+class QString;
 
 class IconProvider : public QObject
 {
diff --git a/src/base/net/smtp.cpp b/src/base/net/smtp.cpp
index 4cffa215c..1e009069a 100644
--- a/src/base/net/smtp.cpp
+++ b/src/base/net/smtp.cpp
@@ -33,10 +33,12 @@
 #include "smtp.h"
 
 #include <QCryptographicHash>
+#include <QDateTime>
 #include <QDebug>
 #include <QHostInfo>
 #include <QStringList>
 #include <QTextCodec>
+
 #ifndef QT_NO_OPENSSL
 #include <QSslSocket>
 #else
diff --git a/src/base/preferences.cpp b/src/base/preferences.cpp
index a96522f5c..81ac30e1f 100644
--- a/src/base/preferences.cpp
+++ b/src/base/preferences.cpp
@@ -29,9 +29,21 @@
 
 #include "preferences.h"
 
+#ifdef Q_OS_MAC
+#include <CoreServices/CoreServices.h>
+#endif
+#ifdef Q_OS_WIN
+#include <shlobj.h>
+#endif
+
+#include <QDateTime>
 #include <QDir>
 #include <QLocale>
+#include <QNetworkCookie>
 #include <QSettings>
+#include <QSize>
+#include <QTime>
+#include <QVariant>
 
 #ifndef DISABLE_GUI
 #include <QApplication>
@@ -40,14 +52,9 @@
 #endif
 
 #ifdef Q_OS_WIN
-#include <shlobj.h>
 #include <QRegularExpression>
 #endif
 
-#ifdef Q_OS_MAC
-#include <CoreServices/CoreServices.h>
-#endif
-
 #include "algorithm.h"
 #include "global.h"
 #include "settingsstorage.h"
diff --git a/src/base/preferences.h b/src/base/preferences.h
index d8aaab2e2..26ed99dbc 100644
--- a/src/base/preferences.h
+++ b/src/base/preferences.h
@@ -30,16 +30,17 @@
 #ifndef PREFERENCES_H
 #define PREFERENCES_H
 
-#include <QDateTime>
 #include <QList>
-#include <QNetworkCookie>
-#include <QSize>
 #include <QStringList>
-#include <QTime>
-#include <QVariant>
 
 #include "base/utils/net.h"
 
+class QDateTime;
+class QNetworkCookie;
+class QSize;
+class QTime;
+class QVariant;
+
 enum SchedulerDays
 {
     EVERY_DAY,
@@ -74,8 +75,6 @@ namespace DNS
     };
 }
 
-class SettingsStorage;
-
 class Preferences : public QObject
 {
     Q_OBJECT
diff --git a/src/base/private/profile_p.cpp b/src/base/private/profile_p.cpp
index 656beeebf..e5a211cc8 100644
--- a/src/base/private/profile_p.cpp
+++ b/src/base/private/profile_p.cpp
@@ -31,8 +31,6 @@
 
 #include <QCoreApplication>
 
-#include "base/utils/fs.h"
-
 Private::Profile::Profile(const QString &configurationName)
     : m_configurationSuffix {configurationName.isEmpty() ? QString() : QLatin1Char('_') + configurationName}
 {
diff --git a/src/base/profile.h b/src/base/profile.h
index 34b627a10..290248105 100644
--- a/src/base/profile.h
+++ b/src/base/profile.h
@@ -33,8 +33,8 @@
 #include <memory>
 
 #include <QSettings>
-#include <QString>
 
+class QString;
 class Application;
 
 namespace Private
diff --git a/src/base/rss/rss_autodownloader.cpp b/src/base/rss/rss_autodownloader.cpp
index 4a8609b3f..10513ac9d 100644
--- a/src/base/rss/rss_autodownloader.cpp
+++ b/src/base/rss/rss_autodownloader.cpp
@@ -37,6 +37,7 @@
 #include <QSaveFile>
 #include <QThread>
 #include <QTimer>
+#include <QUrl>
 #include <QVariant>
 #include <QVector>
 
diff --git a/src/base/rss/rss_autodownloadrule.h b/src/base/rss/rss_autodownloadrule.h
index 15fd113fb..15e22b735 100644
--- a/src/base/rss/rss_autodownloadrule.h
+++ b/src/base/rss/rss_autodownloadrule.h
@@ -29,10 +29,10 @@
 
 #pragma once
 
-#include <QDateTime>
 #include <QSharedDataPointer>
 #include <QVariant>
 
+class QDateTime;
 class QJsonObject;
 class QRegularExpression;
 class TriStateBool;
diff --git a/src/base/search/searchhandler.h b/src/base/search/searchhandler.h
index fae52d05c..3cf71318a 100644
--- a/src/base/search/searchhandler.h
+++ b/src/base/search/searchhandler.h
@@ -32,6 +32,7 @@
 #include <QByteArray>
 #include <QList>
 #include <QObject>
+#include <QString>
 
 class QProcess;
 class QTimer;
diff --git a/src/base/settingvalue.h b/src/base/settingvalue.h
index e3ff237c1..b2d13b353 100644
--- a/src/base/settingvalue.h
+++ b/src/base/settingvalue.h
@@ -33,7 +33,6 @@
 
 #include <QMetaEnum>
 #include <QString>
-#include <QVariant>
 
 #include "settingsstorage.h"
 
diff --git a/src/base/utils/fs.cpp b/src/base/utils/fs.cpp
index ae9d1d31a..ab29a9a2c 100644
--- a/src/base/utils/fs.cpp
+++ b/src/base/utils/fs.cpp
@@ -34,15 +34,6 @@
 #include <memory>
 #endif
 
-#include <QCoreApplication>
-#include <QDebug>
-#include <QDir>
-#include <QDirIterator>
-#include <QFile>
-#include <QFileInfo>
-#include <QStorageInfo>
-#include <QRegularExpression>
-
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -58,6 +49,15 @@
 #include <unistd.h>
 #endif
 
+#include <QCoreApplication>
+#include <QDebug>
+#include <QDir>
+#include <QDirIterator>
+#include <QFile>
+#include <QFileInfo>
+#include <QStorageInfo>
+#include <QRegularExpression>
+
 #include "base/bittorrent/torrenthandle.h"
 #include "base/global.h"
 
diff --git a/src/base/utils/random.cpp b/src/base/utils/random.cpp
index fde12462e..ef46fe860 100644
--- a/src/base/utils/random.cpp
+++ b/src/base/utils/random.cpp
@@ -43,6 +43,8 @@
 #include <cstdio>
 #endif
 
+#include <QString>
+
 #include "misc.h"
 
 namespace
diff --git a/src/gui/optionsdialog.cpp b/src/gui/optionsdialog.cpp
index 14a7d34b7..5ae565937 100644
--- a/src/gui/optionsdialog.cpp
+++ b/src/gui/optionsdialog.cpp
@@ -29,6 +29,7 @@
 #include "optionsdialog.h"
 
 #include <cstdlib>
+#include <limits>
 
 #include <QApplication>
 #include <QCloseEvent>
@@ -62,8 +63,8 @@
 #include "advancedsettings.h"
 #include "app/application.h"
 #include "banlistoptionsdialog.h"
-#include "ipsubnetwhitelistoptionsdialog.h"
 #include "guiiconprovider.h"
+#include "ipsubnetwhitelistoptionsdialog.h"
 #include "rss/automatedrssdownloader.h"
 #include "scanfoldersdelegate.h"
 #include "ui_optionsdialog.h"
diff --git a/src/gui/optionsdialog.h b/src/gui/optionsdialog.h
index 4e3a2d841..1565fdd19 100644
--- a/src/gui/optionsdialog.h
+++ b/src/gui/optionsdialog.h
@@ -29,7 +29,6 @@
 #ifndef OPTIONSDIALOG_H
 #define OPTIONSDIALOG_H
 
-#include <QButtonGroup>
 #include <QDialog>
 
 class QAbstractButton;
diff --git a/src/gui/properties/propertieswidget.cpp b/src/gui/properties/propertieswidget.cpp
index eb10e0d0c..b6e60dd06 100644
--- a/src/gui/properties/propertieswidget.cpp
+++ b/src/gui/properties/propertieswidget.cpp
@@ -29,12 +29,14 @@
 #include "propertieswidget.h"
 
 #include <QAction>
+#include <QDateTime>
 #include <QDebug>
 #include <QDir>
 #include <QHeaderView>
 #include <QListWidgetItem>
 #include <QMenu>
 #include <QSplitter>
+#include <QShortcut>
 #include <QStackedWidget>
 #include <QThread>
 #include <QUrl>
diff --git a/src/gui/properties/propertieswidget.h b/src/gui/properties/propertieswidget.h
index de8b22d2d..c0c5750d3 100644
--- a/src/gui/properties/propertieswidget.h
+++ b/src/gui/properties/propertieswidget.h
@@ -29,14 +29,13 @@
 #ifndef PROPERTIESWIDGET_H
 #define PROPERTIESWIDGET_H
 
-#include <QShortcut>
+#include <QList>
 #include <QWidget>
 
 #include "base/bittorrent/torrenthandle.h"
 
-class QAction;
 class QPushButton;
-class QTimer;
+class QShortcut;
 class QTreeView;
 
 class DownloadedPiecesBar;
@@ -45,8 +44,6 @@ class PeerListWidget;
 class PieceAvailabilityBar;
 class PropListDelegate;
 class PropTabBar;
-class SpeedWidget;
-class torrent_file;
 class TorrentContentFilterModel;
 class TrackerListWidget;
 
diff --git a/src/gui/properties/speedwidget.cpp b/src/gui/properties/speedwidget.cpp
index 0ab151413..b3a1d3b3a 100644
--- a/src/gui/properties/speedwidget.cpp
+++ b/src/gui/properties/speedwidget.cpp
@@ -28,13 +28,12 @@
 
 #include "speedwidget.h"
 
-#include <QVBoxLayout>
+#include <QDateTime>
 #include <QHBoxLayout>
 #include <QLabel>
 #include <QMenu>
 #include <QTimer>
-
-#include <libtorrent/session_status.hpp>
+#include <QVBoxLayout>
 
 #include "base/bittorrent/session.h"
 #include "base/bittorrent/sessionstatus.h"
diff --git a/src/gui/properties/speedwidget.h b/src/gui/properties/speedwidget.h
index 148e40f55..79979b2a0 100644
--- a/src/gui/properties/speedwidget.h
+++ b/src/gui/properties/speedwidget.h
@@ -34,10 +34,10 @@
 
 #include "speedplotview.h"
 
-class QVBoxLayout;
 class QHBoxLayout;
 class QLabel;
 class QMenu;
+class QVBoxLayout;
 class PropertiesWidget;
 
 class ComboBoxMenuButton : public QComboBox
diff --git a/src/gui/transferlistdelegate.cpp b/src/gui/transferlistdelegate.cpp
index d64d74e35..7a314310f 100644
--- a/src/gui/transferlistdelegate.cpp
+++ b/src/gui/transferlistdelegate.cpp
@@ -29,6 +29,7 @@
 #include "transferlistdelegate.h"
 
 #include <QApplication>
+#include <QDateTime>
 #include <QModelIndex>
 #include <QPainter>
 #include <QStyleOptionViewItem>
@@ -37,7 +38,6 @@
 #include <QProxyStyle>
 #endif
 
-#include "base/bittorrent/session.h"
 #include "base/bittorrent/torrenthandle.h"
 #include "base/preferences.h"
 #include "base/types.h"
diff --git a/src/webui/api/authcontroller.cpp b/src/webui/api/authcontroller.cpp
index 5798f77ec..1a34f163c 100644
--- a/src/webui/api/authcontroller.cpp
+++ b/src/webui/api/authcontroller.cpp
@@ -28,6 +28,9 @@
 
 #include "authcontroller.h"
 
+#include <QDateTime>
+#include <QString>
+
 #include "base/logger.h"
 #include "base/preferences.h"
 #include "base/utils/password.h"
diff --git a/src/webui/api/authcontroller.h b/src/webui/api/authcontroller.h
index 287aee3da..0dd896473 100644
--- a/src/webui/api/authcontroller.h
+++ b/src/webui/api/authcontroller.h
@@ -29,10 +29,11 @@
 #pragma once
 
 #include <QHash>
-#include <QString>
 
 #include "apicontroller.h"
 
+class QString;
+
 class AuthController : public APIController
 {
     Q_OBJECT
diff --git a/src/webui/webapplication.cpp b/src/webui/webapplication.cpp
index c0b15b001..07bbb68ec 100644
--- a/src/webui/webapplication.cpp
+++ b/src/webui/webapplication.cpp
@@ -29,10 +29,6 @@
 #include "webapplication.h"
 
 #include <algorithm>
-#include <functional>
-#include <queue>
-#include <stdexcept>
-#include <vector>
 
 #include <QDateTime>
 #include <QDebug>
@@ -41,13 +37,13 @@
 #include <QJsonDocument>
 #include <QMimeDatabase>
 #include <QMimeType>
+#include <QNetworkCookie>
 #include <QRegExp>
 #include <QUrl>
 
 #include "base/algorithm.h"
 #include "base/global.h"
 #include "base/http/httperror.h"
-#include "base/iconprovider.h"
 #include "base/logger.h"
 #include "base/preferences.h"
 #include "base/utils/bytearray.h"