diff --git a/toonz/sources/common/tcore/tthread.cpp b/toonz/sources/common/tcore/tthread.cpp
index a487b77..3189b8c 100644
--- a/toonz/sources/common/tcore/tthread.cpp
+++ b/toonz/sources/common/tcore/tthread.cpp
@@ -10,7 +10,7 @@
 #include "tatomicvar.h"
 
 #include "tthread.h"
-#include "tthreadP.h"
+#include "tthreadp.h"
 
 // STL includes
 #include <set>
diff --git a/toonz/sources/common/tsystem/tlogger.cpp b/toonz/sources/common/tsystem/tlogger.cpp
index 15411af..495adf1 100644
--- a/toonz/sources/common/tsystem/tlogger.cpp
+++ b/toonz/sources/common/tsystem/tlogger.cpp
@@ -8,7 +8,7 @@
 #include <fstream>
 #include <set>
 #include <vector>
-#include <qtime>
+#include <QTimer>
 
 using std::endl;
 
diff --git a/toonz/sources/common/tsystem/tsystem.cpp b/toonz/sources/common/tsystem/tsystem.cpp
index 510063d..1ceb34f 100644
--- a/toonz/sources/common/tsystem/tsystem.cpp
+++ b/toonz/sources/common/tsystem/tsystem.cpp
@@ -10,26 +10,26 @@ using namespace std;
 
 #ifndef TNZCORE_LIGHT
 
-#include <qdatetime>
-#include <qstringlist>
-#include <qprocess>
-#include <qdir>
-#include <qfile>
-#include <qfileinfo>
-#include <qsettings>
-#include <qvariant>
-#include <qthread>
-#include <qurl>
-#include <qcoreapplication>
-#include <quuid.h>
+#include <QDateTime>
+#include <QStringList>
+#include <QProcess>
+#include <QDir>
+#include <QFile>
+#include <QFileInfo>
+#include <QSettings>
+#include <QVariant>
+#include <QThread>
+#include <QUrl>
+#include <QCoreApplication>
+#include <QUuid>
 
 #ifdef WIN32
 #include <qdesktopservices>
 #include <qhostinfo>
 #include <shlobj.h>
 #else
-#include <qdesktopservices>
-#include <qhostinfo>
+#include <QDesktopServices>
+#include <QHostInfo>
 #endif
 
 #include <QStringList>
diff --git a/toonz/sources/image/tzl/tiio_tzl.cpp b/toonz/sources/image/tzl/tiio_tzl.cpp
index c7ec77d..62fbbb9 100644
--- a/toonz/sources/image/tzl/tiio_tzl.cpp
+++ b/toonz/sources/image/tzl/tiio_tzl.cpp
@@ -21,7 +21,7 @@
 #include "tconvert.h"
 #include "trasterimage.h"
 
-#include "QByteArray.h"
+#include <QByteArray>
 
 #if !defined(TNZ_LITTLE_ENDIAN)
 TNZ_LITTLE_ENDIAN undefined !!
diff --git a/toonz/sources/include/tcontenthistory.h b/toonz/sources/include/tcontenthistory.h
index 230ad82..a563279 100644
--- a/toonz/sources/include/tcontenthistory.h
+++ b/toonz/sources/include/tcontenthistory.h
@@ -5,8 +5,8 @@
 
 #include "tcommon.h"
 #include "tfilepath.h"
-#include <qstring>
-#include <qdatetime>
+#include <QString>
+#include <QDateTime>
 #include <map>
 #include <set>
 
diff --git a/toonz/sources/include/tconvert.h b/toonz/sources/include/tconvert.h
index ff0b77e..c496867 100644
--- a/toonz/sources/include/tconvert.h
+++ b/toonz/sources/include/tconvert.h
@@ -73,7 +73,7 @@ DVAPI wstring toUpper(wstring a);
 DVAPI wstring toLower(wstring a);
 
 #ifndef TNZCORE_LIGHT
-#include <qstring>
+#include <QString>
 
 inline bool fromStr(int &v, QString s)
 {
diff --git a/toonz/sources/include/tfarmtask.h b/toonz/sources/include/tfarmtask.h
index b9d8f51..8518848 100644
--- a/toonz/sources/include/tfarmtask.h
+++ b/toonz/sources/include/tfarmtask.h
@@ -3,7 +3,7 @@
 #ifndef TFARMTASK_H
 #define TFARMTASK_H
 
-#include <qdatetime>
+#include <QDateTime>
 #include "tpersist.h"
 #include "tfarmplatforms.h"
 #include "tfilepath.h"
diff --git a/toonz/sources/include/tmsgcore.h b/toonz/sources/include/tmsgcore.h
index d5394a7..8e328da 100644
--- a/toonz/sources/include/tmsgcore.h
+++ b/toonz/sources/include/tmsgcore.h
@@ -2,7 +2,7 @@
 
 #pragma once
 
-#include <qobject>
+#include <QObject>
 #include <set>
 
 #include "tcommon.h"
diff --git a/toonz/sources/include/toonz/scriptbinding_files.h b/toonz/sources/include/toonz/scriptbinding_files.h
index 08371f5..2611738 100644
--- a/toonz/sources/include/toonz/scriptbinding_files.h
+++ b/toonz/sources/include/toonz/scriptbinding_files.h
@@ -6,7 +6,7 @@
 #include "toonz/scriptbinding.h"
 #include "tfilepath.h"
 
-#include <qdatetime.h>
+#include <QDateTime>
 
 namespace TScriptBinding
 {
diff --git a/toonz/sources/include/toonz/ttileset.h b/toonz/sources/include/toonz/ttileset.h
index 360188d..fc675ea 100644
--- a/toonz/sources/include/toonz/ttileset.h
+++ b/toonz/sources/include/toonz/ttileset.h
@@ -4,7 +4,7 @@
 #define TTILESET_HEADER
 
 #include "trastercm.h"
-#include <qstring>
+#include <QString>
 
 #undef DVAPI
 #undef DVVAR
diff --git a/toonz/sources/include/toonzqt/schematicgroupeditor.h b/toonz/sources/include/toonzqt/schematicgroupeditor.h
index b7b4447..0d7f403 100644
--- a/toonz/sources/include/toonzqt/schematicgroupeditor.h
+++ b/toonz/sources/include/toonzqt/schematicgroupeditor.h
@@ -4,7 +4,7 @@
 #define SCHEMATICGROUPEDITOR_H
 
 #include "tcommon.h"
-#include <QGraphicsItem.h>
+#include <QGraphicsItem>
 #include "tgeometry.h"
 
 #undef DVAPI
diff --git a/toonz/sources/include/tscanner.h b/toonz/sources/include/tscanner.h
index 13d45e1..4444c74 100644
--- a/toonz/sources/include/tscanner.h
+++ b/toonz/sources/include/tscanner.h
@@ -9,7 +9,7 @@
 
 #include "trasterimage.h"
 #include <set>
-#include <qstring>
+#include <QString>
 #undef DVAPI
 #undef DVVAR
 #ifdef TNZBASE_EXPORTS
diff --git a/toonz/sources/include/tsystem.h b/toonz/sources/include/tsystem.h
index 79bacc7..b7209d4 100644
--- a/toonz/sources/include/tsystem.h
+++ b/toonz/sources/include/tsystem.h
@@ -28,7 +28,7 @@
 
 #ifndef TNZCORE_LIGHT
 
-#include <qdatetime>
+#include <QDateTime>
 
 DVAPI ostream &operator<<(ostream &out, const QDateTime &t);
 
diff --git a/toonz/sources/tnztools/plastictool.cpp b/toonz/sources/tnztools/plastictool.cpp
index 3fe5bf3..ea58842 100644
--- a/toonz/sources/tnztools/plastictool.cpp
+++ b/toonz/sources/tnztools/plastictool.cpp
@@ -37,7 +37,7 @@
 // Qt includes
 #include <QApplication>
 #include <QString>
-#include <QToolbar>
+#include <QToolBar>
 #include <QPushButton>
 #include <QLabel>
 #include <QClipboard>
diff --git a/toonz/sources/toonz/batches.cpp b/toonz/sources/toonz/batches.cpp
index c8f2c4c..4a9c5e6 100644
--- a/toonz/sources/toonz/batches.cpp
+++ b/toonz/sources/toonz/batches.cpp
@@ -24,8 +24,8 @@
 
 #include "toonzqt/gutil.h"
 
-#include <qstring>
-#include <qprocess>
+#include <QString>
+#include <QProcess>
 #include <QHostInfo>
 
 namespace
diff --git a/toonz/sources/toonz/batches.h b/toonz/sources/toonz/batches.h
index 1579df4..1b67d24 100644
--- a/toonz/sources/toonz/batches.h
+++ b/toonz/sources/toonz/batches.h
@@ -3,11 +3,11 @@
 #ifndef BATCHES_H
 #define BATCHES_H
 
-#include <qobject>
+#include <QObject>
 #include <map>
 #include <set>
 #include <vector>
-#include <qstring>
+#include <QString>
 #include "tfarmtask.h"
 #include "tfilepath.h"
 #include "tthread.h"
diff --git a/toonz/sources/toonz/filmstripcommand.cpp b/toonz/sources/toonz/filmstripcommand.cpp
index 4061964..f004776 100644
--- a/toonz/sources/toonz/filmstripcommand.cpp
+++ b/toonz/sources/toonz/filmstripcommand.cpp
@@ -16,7 +16,7 @@
 #include "drawingdata.h"
 #include "toonzqt/strokesdata.h"
 #include "toonzqt/rasterimagedata.h"
-#include "timageCache.h"
+#include "timagecache.h"
 #include "tools/toolutils.h"
 #include "toonzqt/icongenerator.h"
 
diff --git a/toonz/sources/toonz/history.h b/toonz/sources/toonz/history.h
index 34cacd5..d260e92 100644
--- a/toonz/sources/toonz/history.h
+++ b/toonz/sources/toonz/history.h
@@ -7,7 +7,7 @@
 #include "tsystem.h"
 
 #include <set>
-#include <qdatetime>
+#include <QDateTime>
 
 class History
 { // singleton
diff --git a/toonz/sources/toonz/insertfxpopup.h b/toonz/sources/toonz/insertfxpopup.h
index 7ef85e5..fe79d69 100644
--- a/toonz/sources/toonz/insertfxpopup.h
+++ b/toonz/sources/toonz/insertfxpopup.h
@@ -4,7 +4,7 @@
 #define INSERTFXPOPUP_H
 
 #include "toonzqt/dvdialog.h"
-#include "tfilePath.h"
+#include "tfilepath.h"
 #include "tstream.h"
 
 // forward declaration
diff --git a/toonz/sources/toonz/matchline.cpp b/toonz/sources/toonz/matchline.cpp
index fa37593..796d188 100644
--- a/toonz/sources/toonz/matchline.cpp
+++ b/toonz/sources/toonz/matchline.cpp
@@ -15,7 +15,7 @@
 // TnzLib includes
 #include "toonz/txsheet.h"
 #include "toonz/toonzscene.h"
-#include "toonz/levelSet.h"
+#include "toonz/levelset.h"
 #include "toonz/txshsimplelevel.h"
 #include "toonz/txshlevelcolumn.h"
 #include "toonz/txshcell.h"
diff --git a/toonz/sources/toonz/mergecmapped.cpp b/toonz/sources/toonz/mergecmapped.cpp
index c7ec7b8..7e00172 100644
--- a/toonz/sources/toonz/mergecmapped.cpp
+++ b/toonz/sources/toonz/mergecmapped.cpp
@@ -4,7 +4,7 @@
 #include "tpalette.h"
 #include "toonz/txsheet.h"
 #include "toonz/toonzscene.h"
-#include "toonz/levelSet.h"
+#include "toonz/levelset.h"
 #include "toonz/txshsimplelevel.h"
 #include "toonz/txshlevelcolumn.h"
 #include "toonz/txshcell.h"
diff --git a/toonz/sources/toonz/mergecolumns.cpp b/toonz/sources/toonz/mergecolumns.cpp
index 6a1ccc5..a6ac143 100644
--- a/toonz/sources/toonz/mergecolumns.cpp
+++ b/toonz/sources/toonz/mergecolumns.cpp
@@ -4,7 +4,7 @@
 #include "tpalette.h"
 #include "toonz/txsheet.h"
 #include "toonz/toonzscene.h"
-#include "toonz/levelSet.h"
+#include "toonz/levelset.h"
 #include "toonz/txshsimplelevel.h"
 #include "toonz/txshlevelcolumn.h"
 #include "toonz/txshcell.h"
diff --git a/toonz/sources/toonz/scenesettingspopup.cpp b/toonz/sources/toonz/scenesettingspopup.cpp
index 937eff5..3bdbee2 100644
--- a/toonz/sources/toonz/scenesettingspopup.cpp
+++ b/toonz/sources/toonz/scenesettingspopup.cpp
@@ -30,7 +30,7 @@
 #include <QComboBox>
 #include <QLabel>
 #include <QApplication>
-#include <QMainwindow>
+#include <QMainWindow>
 #include <QPainter>
 
 using namespace DVGui;
diff --git a/toonz/sources/toonz/viewerdraw.cpp b/toonz/sources/toonz/viewerdraw.cpp
index 1ac57f9..364894e 100644
--- a/toonz/sources/toonz/viewerdraw.cpp
+++ b/toonz/sources/toonz/viewerdraw.cpp
@@ -7,7 +7,7 @@
 #include "toonz/tframehandle.h"
 #include "toonz/tcolumnhandle.h"
 #include "toonz/tobjecthandle.h"
-#include "toonz/cleanupParameters.h"
+#include "toonz/cleanupparameters.h"
 #include "sceneviewer.h"
 #include "ruler.h"
 
diff --git a/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp b/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
index f0448d3..4357333 100644
--- a/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
@@ -8,7 +8,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <search.h>
-#include "YombInputParam.h"
+#include "YOMBInputParam.h"
 //#include "tmsg.h"
 #ifdef WIN32
 #pragma warning(disable : 4996)
diff --git a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.cpp b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.cpp
index ee426ec..e1aa37a 100644
--- a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.cpp
@@ -14,7 +14,7 @@
 #include <string.h>
 #include "YOMBParam.h"
 #include "InputParam.h"
-#include "YombInputParam.h"
+#include "YOMBInputParam.h"
 #include "STColSelPic.h"
 #include "BlurMatrix.h"
 #include "SDef.h"
diff --git a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
index b7d78fe..bcce4cc 100644
--- a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
+++ b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
@@ -15,7 +15,7 @@
 #include "STColSelPic.h"
 #include "SDef.h"
 #include "InputParam.h"
-#include "YombInputParam.h"
+#include "YOMBInputParam.h"
 #include "BlurMatrix.h"
 //#pragma warning(disable: 4786)
 //#include "tmsg.h"
diff --git a/toonz/sources/toonzlib/studiopalettecmd.cpp b/toonz/sources/toonzlib/studiopalettecmd.cpp
index 4edb8a7..6d7e6ec 100644
--- a/toonz/sources/toonzlib/studiopalettecmd.cpp
+++ b/toonz/sources/toonzlib/studiopalettecmd.cpp
@@ -19,7 +19,7 @@
 #include "toonz/sceneproperties.h"
 #include "toonz/toonzfolders.h"
 #include "toonz/txsheet.h"
-#include <QApplication.h>
+#include <QApplication>
 
 #include "historytypes.h"
 
diff --git a/toonz/sources/toonzlib/tlog.cpp b/toonz/sources/toonzlib/tlog.cpp
index 1856536..044f4db 100644
--- a/toonz/sources/toonzlib/tlog.cpp
+++ b/toonz/sources/toonzlib/tlog.cpp
@@ -4,7 +4,7 @@
 //#include "tfilepath.h"
 #include "tfilepath_io.h"
 
-#include <qdatetime>
+#include <QDateTime>
 
 #ifdef WIN32
 #pragma warning(disable : 4996)
diff --git a/toonz/sources/toonzqt/functionviewer.cpp b/toonz/sources/toonzqt/functionviewer.cpp
index a25a806..1c44996 100644
--- a/toonz/sources/toonzqt/functionviewer.cpp
+++ b/toonz/sources/toonzqt/functionviewer.cpp
@@ -18,7 +18,7 @@
 #include "toonz/txsheethandle.h"
 #include "toonz/tobjecthandle.h"
 #include "toonz/tfxhandle.h"
-#include "toonz/tcolumnHandle.h"
+#include "toonz/tcolumnhandle.h"
 #include "toonz/fxdag.h"
 #include "toonz/txshzeraryfxcolumn.h"
 #include "toonz/tcolumnfx.h"
@@ -42,7 +42,7 @@
 #include <QPushButton>
 #include <QStackedWidget>
 #include <QLabel>
-#include <QToolbar>
+#include <QToolBar>
 #include <QAction>
 
 using namespace DVGui;
diff --git a/toonz/sources/toonzqt/schematicviewer.cpp b/toonz/sources/toonzqt/schematicviewer.cpp
index 0626838..8fd0fd0 100644
--- a/toonz/sources/toonzqt/schematicviewer.cpp
+++ b/toonz/sources/toonzqt/schematicviewer.cpp
@@ -31,7 +31,7 @@
 // Qt includes
 #include <QGraphicsSceneMouseEvent>
 #include <QMouseEvent>
-#include <QGraphicsItem.h>
+#include <QGraphicsItem>
 #include <QToolBar>
 #include <QToolButton>
 #include <QMenu>
diff --git a/toonz/sources/toonzqt/spreadsheetviewer.cpp b/toonz/sources/toonzqt/spreadsheetviewer.cpp
index 28ba0fa..7a9a4c1 100644
--- a/toonz/sources/toonzqt/spreadsheetviewer.cpp
+++ b/toonz/sources/toonzqt/spreadsheetviewer.cpp
@@ -8,7 +8,7 @@
 #include <QKeyEvent>
 #include <QWheelEvent>
 #include <QLabel>
-#include <QScrollbar>
+#include <QScrollBar>
 #include <QPainter>
 #include <QGridLayout>
 #include <QPaintEvent>