diff --git a/ChangeLog.txt b/ChangeLog.txt
index ef7bcfce5..9d58a7edb 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -842,7 +842,7 @@
 	  (2014-2-20).
 	* nshlib/Kconfig:  Use CONFIG_DEFAULT_SMALL in selecting default
 	  settings (2014-2-20).
-	* nshlib/nsh_telnetd.c:  Use strncpy vs strcpy to avoid overruning the
+	* nshlib/nsh_telnetd.c:  Use strncpy vs strcpy to avoid overrunning the
 	  username and password buffers.  From Bertold Van den Bergh (2014-2-22).
 	* nshlib/Kconfig, nsh_proccmds.c:  If the CPU load feature and the procfs
 	  features are enabled, then show CPU load used by each thread in the
diff --git a/graphics/nxwidgets/src/cnxstring.cxx b/graphics/nxwidgets/src/cnxstring.cxx
index 692ed2d93..ea95419c8 100644
--- a/graphics/nxwidgets/src/cnxstring.cxx
+++ b/graphics/nxwidgets/src/cnxstring.cxx
@@ -241,7 +241,7 @@ void CNxString::setText(FAR const nxwidget_char_t *text, int nchars)
 /**
  * Set the text in the string.
  *
- * @param text Character to to use as the new data for this string.
+ * @param text Character to use as the new data for this string.
  */
 
 void CNxString::setText(const nxwidget_char_t letter)
diff --git a/graphics/nxwidgets/src/ctext.cxx b/graphics/nxwidgets/src/ctext.cxx
index 1d45e911f..dd9aa13a3 100644
--- a/graphics/nxwidgets/src/ctext.cxx
+++ b/graphics/nxwidgets/src/ctext.cxx
@@ -133,7 +133,7 @@ void CText::setText(FAR const char *text)
 /**
  * Set the text in the string.
  *
- * @param text Character to to use as the new data for this string.
+ * @param text Character to use as the new data for this string.
  */
 
 void CText::setText(const nxwidget_char_t text)
diff --git a/graphics/nxwm/src/cnxterm.cxx b/graphics/nxwm/src/cnxterm.cxx
index 11f3ce8e2..6fd7d8374 100644
--- a/graphics/nxwm/src/cnxterm.cxx
+++ b/graphics/nxwm/src/cnxterm.cxx
@@ -135,7 +135,7 @@ CNxTerm::CNxTerm(CTaskbar *taskbar, CApplicationWindow *window)
   m_taskbar = taskbar;
   m_window  = window;
 
-  // The NxTerm is not runing
+  // The NxTerm is not running
 
   m_pid    = -1;
   m_nxterm = 0;
diff --git a/graphics/nxwm/src/nxwm_main.cxx b/graphics/nxwm/src/nxwm_main.cxx
index a42b2ffd0..bf8ba18f8 100644
--- a/graphics/nxwm/src/nxwm_main.cxx
+++ b/graphics/nxwm/src/nxwm_main.cxx
@@ -355,7 +355,7 @@ static bool createCalibration(void)
       return false;
     }
 
-  // Call StartWindowFactory::create to to create the start window application
+  // Call StartWindowFactory::create to create the start window application
 
   printf("createCalibration: Creating CCalibration\n");
   NxWM::IApplication *calibration = factory->create();
diff --git a/graphics/traveler/src/trv_color.c b/graphics/traveler/src/trv_color.c
index 1c17e3a98..b468e6116 100644
--- a/graphics/traveler/src/trv_color.c
+++ b/graphics/traveler/src/trv_color.c
@@ -540,7 +540,7 @@ void trv_color_free(struct trv_palette_s *pinfo)
 /****************************************************************************
  * Name: trv_color_rgb2pixel
  * Description: Map a RGB triplet into the corresponding pixel.  The
- *   value range of ech RGB value is assume to lie within 0 through
+ *   value range of each RGB value is assumed to lie within 0 through
  *   TRV_PIXEL_MAX.
  ****************************************************************************/
 
diff --git a/graphics/traveler/tools/libwld/wld_rgb2pixel.c b/graphics/traveler/tools/libwld/wld_rgb2pixel.c
index 29b5a1c8f..b53af7798 100644
--- a/graphics/traveler/tools/libwld/wld_rgb2pixel.c
+++ b/graphics/traveler/tools/libwld/wld_rgb2pixel.c
@@ -44,7 +44,7 @@
 /****************************************************************************
  * Name: wld_rgb2pixel
  * Description: Map a RGB triplet into the corresponding pixel.  The
- *   value range of ech RGB value is assume to lie within 0 through
+ *   value range of each RGB value is assumed to lie within 0 through
  *   TRV_PIXEL_MAX.
  ****************************************************************************/
 
diff --git a/graphics/traveler/tools/tcledit/README.txt b/graphics/traveler/tools/tcledit/README.txt
index 9bf0cd419..4298270c6 100644
--- a/graphics/traveler/tools/tcledit/README.txt
+++ b/graphics/traveler/tools/tcledit/README.txt
@@ -37,9 +37,9 @@ Build instuctions
   Then you can use xmfmk to create the Makefile and build the tool:
 
     7. cd apps/graphics/traveler/tools/tcledit
-    8. Review Imakefile.  You will probabaly to to change the APPDIR and TOPDIR paths
-       a minimum.  These are the paths to where you have clones the apps/ repository
-       and the nuttx/ repositories, respectively.
+    8. Review Imakefile.  You will probabaly need to change the APPDIR and
+       TOPDIR paths at a minimum.  These are the paths to where you have
+       cloned the apps/ repository and the nuttx/ repositories, respectively.
     9. xmfmk
    10a. make tcledit
 
diff --git a/graphics/twm4nx/apps/cclock.cxx b/graphics/twm4nx/apps/cclock.cxx
index 45e6ee41c..46f1fd28c 100644
--- a/graphics/twm4nx/apps/cclock.cxx
+++ b/graphics/twm4nx/apps/cclock.cxx
@@ -509,7 +509,7 @@ void CClock::update(void)
   pos.y = CONFIG_TWM4NX_CLOCK_VSPACING;
 
   // Then show each segment LCD
-  // There might be a more efficient way to to this than to erase the entire
+  // There might be a more efficient way to do this than to erase the entire
   // SLCD on each update.
 
   for (int i = 0; i < CLOCK_NDIGITS; i++)
diff --git a/graphics/twm4nx/src/ciconwidget.cxx b/graphics/twm4nx/src/ciconwidget.cxx
index f6b35173b..134163aeb 100644
--- a/graphics/twm4nx/src/ciconwidget.cxx
+++ b/graphics/twm4nx/src/ciconwidget.cxx
@@ -293,7 +293,7 @@ bool CIconWidget::initialize(FAR CWindow *parent,
   image->setRaisesEvents(true);
   image->setDraggable(true);
 
-  // Add the CIconImage to to the containing widget
+  // Add the CIconImage to the containing widget
 
   image->addWidgetEventHandler(this);
   addWidget(image);
@@ -332,7 +332,7 @@ bool CIconWidget::initialize(FAR CWindow *parent,
   topLabel->setRaisesEvents(true);
   topLabel->setDraggable(true);
 
-  // Add the top label to to the containing widget
+  // Add the top label to the containing widget
 
   topLabel->addWidgetEventHandler(this);
   addWidget(topLabel);
@@ -378,7 +378,7 @@ bool CIconWidget::initialize(FAR CWindow *parent,
       bottomLabel->setRaisesEvents(true);
       bottomLabel->setDraggable(true);
 
-      // Add the top label to to the containing widget
+      // Add the top label to the containing widget
 
       bottomLabel->addWidgetEventHandler(this);
       addWidget(bottomLabel);
diff --git a/include/graphics/nxwidgets/cnxstring.hxx b/include/graphics/nxwidgets/cnxstring.hxx
index 4f3fa7d1d..0d58431b7 100644
--- a/include/graphics/nxwidgets/cnxstring.hxx
+++ b/include/graphics/nxwidgets/cnxstring.hxx
@@ -281,7 +281,7 @@ namespace NXWidgets
     /**
      * Set the 8-bit C-string text in the string.
      *
-     * @param text Character to to use as the new data for this string.
+     * @param text Character to use as the new data for this string.
      */
 
     void setText(const nxwidget_char_t text);
diff --git a/include/graphics/nxwidgets/ctext.hxx b/include/graphics/nxwidgets/ctext.hxx
index 6a0158228..608ac8e60 100644
--- a/include/graphics/nxwidgets/ctext.hxx
+++ b/include/graphics/nxwidgets/ctext.hxx
@@ -171,7 +171,7 @@ namespace NXWidgets
     /**
      * Set the text in the string.
      *
-     * @param text Character to to use as the new data for this string.
+     * @param text Character to use as the new data for this string.
      */
 
     virtual void setText(const nxwidget_char_t text);
diff --git a/netutils/dhcpd/dhcpd.c b/netutils/dhcpd/dhcpd.c
index 89d2758b7..6c6603f84 100644
--- a/netutils/dhcpd/dhcpd.c
+++ b/netutils/dhcpd/dhcpd.c
@@ -290,7 +290,7 @@ static inline void dhcpd_arpupdate(FAR uint8_t *ipaddr, FAR uint8_t *hwaddr)
 {
   struct sockaddr_in inaddr;
 
-  /* Put the protocol address in a standard form. ipaddr is assume to be in
+  /* Put the protocol address in a standard form. ipaddr is assumed to be in
    * network order by the memcpy.
    */
 
diff --git a/netutils/ftpc/ftpc_listdir.c b/netutils/ftpc/ftpc_listdir.c
index d9a52973a..7985ff1af 100644
--- a/netutils/ftpc/ftpc_listdir.c
+++ b/netutils/ftpc/ftpc_listdir.c
@@ -329,7 +329,7 @@ FAR struct ftpc_dirlist_s *ftpc_listdir(SESSION handle,
       int tmpret = ftpc_cmd(session, "CWD %s", session->currdir);
       if (tmpret != OK)
         {
-          nerr("ERROR: CWD back to to %s failed\n", session->currdir);
+          nerr("ERROR: CWD back to %s failed\n", session->currdir);
         }
     }
 
diff --git a/system/zmodem/zm.h b/system/zmodem/zm.h
index ed553835f..6e888d0f4 100644
--- a/system/zmodem/zm.h
+++ b/system/zmodem/zm.h
@@ -559,7 +559,7 @@ ssize_t zm_remwrite(int fd, FAR const uint8_t *buffer, size_t buflen);
  *   necessary.
  *
  * NOTE:  Not re-entrant.  CR-LF sequences that span buffer boundaries are
- * not guaranteed to to be handled correctly.
+ * not guaranteed to be handled correctly.
  *
  ****************************************************************************/
 
diff --git a/system/zmodem/zm_send.c b/system/zmodem/zm_send.c
index b1f27f22d..a2cbbeda2 100644
--- a/system/zmodem/zm_send.c
+++ b/system/zmodem/zm_send.c
@@ -476,7 +476,7 @@ static int zms_zrinit(FAR struct zm_state_s *pzm)
     }
 #endif
 
-  /* Otherwise, we have to to ZCRCW */
+  /* Otherwise, we have to do ZCRCW */
 
   else
     {
diff --git a/system/zmodem/zm_utils.c b/system/zmodem/zm_utils.c
index cc628ce74..a325a8723 100644
--- a/system/zmodem/zm_utils.c
+++ b/system/zmodem/zm_utils.c
@@ -343,7 +343,7 @@ int zm_putc(int fd, uint8_t ch)
  *   necessary.
  *
  * NOTE:  Not re-entrant.  CR-LF sequences that span buffer boundaries are
- * not guaranteed to to be handled correctly.
+ * not guaranteed to be handled correctly.
  *
  ****************************************************************************/