diff --git a/doc/how_to_build_bsd.md b/doc/how_to_build_bsd.md
index 2c56fec..162da27 100644
--- a/doc/how_to_build_bsd.md
+++ b/doc/how_to_build_bsd.md
@@ -1,4 +1,4 @@
-# Setting up the development environment for BSD operatings systems such as NetBSD, FreeBSD, Dragonfly BSD, or OpenBSD
+# Setting up the development environment for BSD operating systems such as NetBSD, FreeBSD, Dragonfly BSD, or OpenBSD
 
 ## Required software
 
diff --git a/toonz/sources/image/tzl/tiio_tzl.cpp b/toonz/sources/image/tzl/tiio_tzl.cpp
index b944dc7..e375e5c 100644
--- a/toonz/sources/image/tzl/tiio_tzl.cpp
+++ b/toonz/sources/image/tzl/tiio_tzl.cpp
@@ -696,14 +696,14 @@ void TLevelWriterTzl::writeHeader(const TDimension &size) {
   assert(m_frameCountPos == 8 + CREATOR_LENGTH + 3 * sizeof(TINT32));
 
   // I put the place for the frameCount, which I will write in this position at
-  // the end  (see in the distructor)
+  // the end  (see in the destructor)
   tfwrite(&intval, 1, m_chan);
   // I put the place for the offsetTableOffset, which I will write in this
-  // position at the end  (see in the distructor)
+  // position at the end  (see in the destructor)
   intval = 0;
   tfwrite(&intval, 1, m_chan);
   // I put the place for the iconOffsetTableOffset, which I will write in this
-  // position at the end  (see in the distructor)
+  // position at the end  (see in the destructor)
   tfwrite(&intval, 1, m_chan);
   tfwrite(codec, codecLen, m_chan);
 }
diff --git a/toonz/sources/stdfx/iwa_motionblurfx.cpp b/toonz/sources/stdfx/iwa_motionblurfx.cpp
index b29a588..3b62aa4 100644
--- a/toonz/sources/stdfx/iwa_motionblurfx.cpp
+++ b/toonz/sources/stdfx/iwa_motionblurfx.cpp
@@ -583,7 +583,7 @@ void Iwa_MotionBlurCompFx::composeBackgroundExposure_CPU(
       bgExposure.y *= (*bg_p).w;
       bgExposure.z *= (*bg_p).w;
 
-      /* Over composte with front layers */
+      /* Over composite with front layers */
       (*out_p).x = (*out_p).x + bgExposure.x * (1.0f - (*out_p).w);
       (*out_p).y = (*out_p).y + bgExposure.y * (1.0f - (*out_p).w);
       (*out_p).z = (*out_p).z + bgExposure.z * (1.0f - (*out_p).w);
diff --git a/toonz/sources/stdfx/iwa_rainbow_intensity.h b/toonz/sources/stdfx/iwa_rainbow_intensity.h
index 7c43459..1bf8120 100644
--- a/toonz/sources/stdfx/iwa_rainbow_intensity.h
+++ b/toonz/sources/stdfx/iwa_rainbow_intensity.h
@@ -2,7 +2,7 @@
 
 #ifndef RAINBOW_INTENSITY_H
 #define RAINBOW_INTENSITY_H
-// Scattering Intensity from water droplet for each wavelengh
+// Scattering Intensity from water droplet for each wavelength
 // and scattering angle
 // Numerical computation is done with MiePlot by Philip Laven
 // Parameters
diff --git a/toonz/sources/stdfx/iwa_soapbubblefx.cpp b/toonz/sources/stdfx/iwa_soapbubblefx.cpp
index 5a2eccf..ecf1bd7 100644
--- a/toonz/sources/stdfx/iwa_soapbubblefx.cpp
+++ b/toonz/sources/stdfx/iwa_soapbubblefx.cpp
@@ -627,7 +627,7 @@ void Iwa_SoapBubbleFx::do_createBlurFilter(float* dst_p, int size,
       if (length2 >= radius2)
         *tmp_p = 0.0f;
       else {
-        /* normalize distace from the filter center, to 0-1 */
+        /* normalize distance from the filter center, to 0-1 */
         *tmp_p = 1.0f - std::sqrt(length2) / radius;
         sum += *tmp_p;
       }
diff --git a/toonz/sources/toonz/ObjectTracker.cpp b/toonz/sources/toonz/ObjectTracker.cpp
index 4765b19..bd9270a 100644
--- a/toonz/sources/toonz/ObjectTracker.cpp
+++ b/toonz/sources/toonz/ObjectTracker.cpp
@@ -66,7 +66,7 @@ CObjectTracker::CObjectTracker(int imW, int imH, bool _colorimage,
 };
 
 //--------------------------------------------------------------------------------------------------------
-// Distructor
+// Destructor
 CObjectTracker::~CObjectTracker() {}
 
 //--------------------------------------------------------------------------------------------------------
diff --git a/toonz/sources/toonz/cellkeyframeselection.cpp b/toonz/sources/toonz/cellkeyframeselection.cpp
index 44a9620..23844fa 100644
--- a/toonz/sources/toonz/cellkeyframeselection.cpp
+++ b/toonz/sources/toonz/cellkeyframeselection.cpp
@@ -76,7 +76,7 @@ void TCellKeyframeSelection::copyCellsKeyframes() {
                                startPos);
     data->setKeyframeData(keyframeData);
   }
-  // Set the cliboard
+  // Set the clipboard
   QClipboard *clipboard = QApplication::clipboard();
   clipboard->setMimeData(data, QClipboard::Clipboard);
 }
diff --git a/toonz/sources/toonz/drawingdata.cpp b/toonz/sources/toonz/drawingdata.cpp
index 5698eb9..afcc099 100644
--- a/toonz/sources/toonz/drawingdata.cpp
+++ b/toonz/sources/toonz/drawingdata.cpp
@@ -452,7 +452,7 @@ DrawingData::~DrawingData() {
 
 void DrawingData::releaseData() {
   // do it when you're sure you no t need images anymore... (for example in an
-  // undo distructor)
+  // undo destructor)
   // int i;
   // for(i=0; i<m_imageSet.size(); i++)
   //  TImageCache::instance()->remove(m_imageSet[i]);
diff --git a/toonz/sources/toonz/flipbook.cpp b/toonz/sources/toonz/flipbook.cpp
index ac550ac..ddb542b 100644
--- a/toonz/sources/toonz/flipbook.cpp
+++ b/toonz/sources/toonz/flipbook.cpp
@@ -1210,7 +1210,7 @@ void FlipBook::setLevel(const TFilePath &fp, TPalette *palette, int from,
                                  m_framesCount);                         // to
       }
 
-      // An old archived bug says that simulatenous open for read of the same
+      // An old archived bug says that simultaneous open for read of the same
       // tlv are not allowed...
       // if(m_lr && m_lr->getFilePath().getType()=="tlv")
       //  m_lr = TLevelReaderP();
@@ -1644,7 +1644,7 @@ TImageP FlipBook::getCurrentImage(int frame) {
       m_loadboxes[id] = showSub ? m_loadbox : TRect();
     }
 
-    // An old archived bug says that simulatenous open for read of the same tlv
+    // An old archived bug says that simultaneous open for read of the same tlv
     // are not allowed...
     // if(fp.getType()=="tlv")
     //  m_lr = TLevelReaderP();
diff --git a/toonz/sources/toonz/previewer.cpp b/toonz/sources/toonz/previewer.cpp
index 8dbafd8..bc96311 100644
--- a/toonz/sources/toonz/previewer.cpp
+++ b/toonz/sources/toonz/previewer.cpp
@@ -352,7 +352,7 @@ void Previewer::Imp::updateRenderSettings() {
   else
     renderSettings.m_shrinkY = renderSettings.m_shrinkX = 1;
 
-  // In case the settings changee, erase all previously cached images
+  // In case the settings changed, erase all previously cached images
   if (renderSettings != m_renderSettings) {
     m_renderSettings = renderSettings;
 
diff --git a/toonz/sources/toonz/xsheetviewer.h b/toonz/sources/toonz/xsheetviewer.h
index 18090e7..af8ee07 100644
--- a/toonz/sources/toonz/xsheetviewer.h
+++ b/toonz/sources/toonz/xsheetviewer.h
@@ -191,7 +191,7 @@ class XsheetViewer final : public QFrame, public SaveLoadQSettings {
 
   QColor m_lightLightBgColor;
   QColor m_lightBgColor;
-  QColor m_bgColor;  // row area backgroound
+  QColor m_bgColor;  // row area background
   QColor m_darkBgColor;
   QColor m_lightLineColor;  // horizontal lines (146,144,146)
   QColor m_darkLineColor;
diff --git a/toonz/sources/toonz/xshrowviewer.h b/toonz/sources/toonz/xshrowviewer.h
index b74912d..e69c915 100644
--- a/toonz/sources/toonz/xshrowviewer.h
+++ b/toonz/sources/toonz/xshrowviewer.h
@@ -64,7 +64,7 @@ class RowArea final : public QWidget {
 
   // Return when the item-menu setAutoMarkers can be enabled.
   bool canSetAutoMarkers();
-  // Return the number of the last non-empty cell finded. You can set the
+  // Return the number of the last non-empty cell found. You can set the
   // direction of the search.
   int getNonEmptyCell(int row, int column, Direction);
 
diff --git a/toonz/sources/toonzlib/Naa2TlvConverter.cpp b/toonz/sources/toonzlib/Naa2TlvConverter.cpp
index d3ff867..45c90b1 100644
--- a/toonz/sources/toonzlib/Naa2TlvConverter.cpp
+++ b/toonz/sources/toonzlib/Naa2TlvConverter.cpp
@@ -733,7 +733,7 @@ void Naa2TlvConverter::assignColorTypes() {
 
 //-----------------------------------------------------------------------------
 
-void Naa2TlvConverter::addBorderInks()  // add syntethic inks: lines between two
+void Naa2TlvConverter::addBorderInks()  // add synthetic inks: lines between two
                                         // adjacent fill-regions
 {
   int lx                   = m_regionRas->getLx();