diff --git a/calendar/base/content/calendar-recurrence-dialog.xul b/calendar/base/content/calendar-recurrence-dialog.xul
index d1ec37afdd1..65594d02e2a 100644
--- a/calendar/base/content/calendar-recurrence-dialog.xul
+++ b/calendar/base/content/calendar-recurrence-dialog.xul
@@ -184,7 +184,7 @@
             <hbox align="center">
               <textbox id="repeat-ntimes-count" size="3" value="5" oninput="validateIntegerRange(event, 1, 0x7FFF); updateAccept();"/>
               <spacer flex="0.5"/>
-              <label value="&repeat.units.occurence.both;"/>
+              <label value="&repeat.units.occurrence.both;"/>
               <spacer flex="1"/>
             </hbox>
           </row>
diff --git a/calendar/base/public/calICalendar.idl b/calendar/base/public/calICalendar.idl
index 01baa76a28f..97588d18a62 100644
--- a/calendar/base/public/calICalendar.idl
+++ b/calendar/base/public/calICalendar.idl
@@ -80,8 +80,8 @@ interface calICalendar : nsISupports
 
   /**
    * Setting this URI causes the calendar to be (re)loaded.
-   * This is not an unique indentifier! It is also not unchangeable. Don't
-   * use it to indentify a calandar, use the id attribute for that purpose.
+   * This is not an unique identifier! It is also not unchangeable. Don't
+   * use it to identify a calendar, use the id attribute for that purpose.
    */
   attribute nsIURI uri;
 
@@ -308,12 +308,12 @@ interface calICalendar : nsISupports
    *   as follows to make for the least amount of pain when
    *   migrating existing frontend code:
    *
-   *     The events are sorted based on the order of their next occurence
-   *     if they recur in the future or their last occurence in the past
+   *     The events are sorted based on the order of their next occurrence
+   *     if they recur in the future or their last occurrence in the past
    *     otherwise.  Here's a presentation of the sort criteria using the
    *     time axis:
    *   
-   *     -----(Last occurence of Event1)---(Last occurence of Event2)----(Now)----(Next occurence of Event3)---->
+   *     -----(Last occurrence of Event1)---(Last occurrence of Event2)----(Now)----(Next occurrence of Event3)---->
    *
    *     (Note that Event1 and Event2 will not recur in the future.)
    *
@@ -321,8 +321,8 @@ interface calICalendar : nsISupports
    *   at some point in the future.
    *
    * Note that the range is intended to act as a mask on the
-   * occurences, not just the initial recurring items.  So if a
-   * getItems() call without ITEM_FILTER_CLASS_OCCURENCES is made, all
+   * occurrences, not just the initial recurring items.  So if a
+   * getItems() call without ITEM_FILTER_CLASS_occurrenceS is made, all
    * events and todos which have occurrences inside the range should
    * be returned, even if some of those events or todos themselves
    * live outside the range.
diff --git a/calendar/base/public/calICalendarView.idl b/calendar/base/public/calICalendarView.idl
index 65536487fe2..529de5aba92 100644
--- a/calendar/base/public/calICalendarView.idl
+++ b/calendar/base/public/calICalendarView.idl
@@ -58,7 +58,7 @@ interface calICalendarView : nsISupports
   /**
    * the calendar that this view is displaying
    */
-  attribute calICalendar displayCalender;
+  attribute calICalendar displayCalendar;
 
   /**
    * the controller for this view
diff --git a/calendar/base/public/calICalendarViewController.idl b/calendar/base/public/calICalendarViewController.idl
index 5d22c04f1dc..df5abd6f833 100644
--- a/calendar/base/public/calICalendarViewController.idl
+++ b/calendar/base/public/calICalendarViewController.idl
@@ -92,7 +92,7 @@ interface calICalendarViewController : nsISupports
    *
    * @param aCount          The number of events in the array
    * @param aOccurrences    An array of Items/Occurrences to delete
-   * @param aUseParentItems If set, each occurence will have its parent item
+   * @param aUseParentItems If set, each occurrence will have its parent item
    *                        deleted.
    * @param aDoNotConfirm   If set, the events will be deleted without
    *                        confirmation.
diff --git a/calendar/base/public/calIDecoratedView.idl b/calendar/base/public/calIDecoratedView.idl
index 5f1737d0bee..de462a8898d 100644
--- a/calendar/base/public/calIDecoratedView.idl
+++ b/calendar/base/public/calIDecoratedView.idl
@@ -81,7 +81,7 @@ interface calIDecoratedView : nsISupports
    * The displayCalendar of the embedded calICalendarView.  This *must* be set
    * prior to calling goToDay the first time.
    */
-  attribute calICalendar displayCalender;
+  attribute calICalendar displayCalendar;
 
   /**
    * The controller of the calICalendarView that is embedded
diff --git a/calendar/libical/src/libical/vcomponent.cpp b/calendar/libical/src/libical/vcomponent.cpp
index cc4fc6b0861..49f0d595596 100644
--- a/calendar/libical/src/libical/vcomponent.cpp
+++ b/calendar/libical/src/libical/vcomponent.cpp
@@ -484,7 +484,7 @@ bool VComponent::remove(VComponent& fromVC, bool ignoreValue){
     return true;
 }
 /* removeMissing == true: remove properties that are missing from fromC */
-/* todo: only change the first occurence of the property */
+/* todo: only change the first occurrence of the property */
 /* todo: removeMissing is not implemented */
 bool VComponent::update(VComponent& fromC, bool removeMissing){
 
diff --git a/calendar/libical/src/libicalss/icalbdbset.c b/calendar/libical/src/libicalss/icalbdbset.c
index 6b11e467417..2bee3cff7dc 100644
--- a/calendar/libical/src/libicalss/icalbdbset.c
+++ b/calendar/libical/src/libicalss/icalbdbset.c
@@ -1293,7 +1293,7 @@ icalsetiter icalbdbset_begin_component(icalset* set, icalcomponent_kind kind, ic
                     itr.last_component = NULL;
                     icalrecur_iterator_free(itr.ritr);
                     itr.ritr = NULL;
-                    /* no matched occurence */
+                    /* no matched occurrence */
                     goto getNextComp;
                 } else {
                     itr.last_component = comp;
@@ -1399,8 +1399,8 @@ icalcomponent* icalbdbset_form_a_matched_recurrence_component(icalsetiter* itr)
             itr->last_component = NULL;
             icalrecur_iterator_free(itr->ritr);
             itr->ritr = NULL;
-            /* no more pending matched occurence,
-             * all the pending matched occurences have been returned */
+            /* no more pending matched occurrence,
+             * all the pending matched occurrences have been returned */
             return NULL;
         } else {
             itr->last_component = comp;
@@ -1450,7 +1450,7 @@ icalcomponent* icalbdbsetiter_to_next(icalset *set, icalsetiter* i)
 
     do {
 
-        /* no pending occurence, read the next component */
+        /* no pending occurrence, read the next component */
         if (i->last_component == NULL) {
             comp = icalcompiter_next(&(i->iter));
         }
@@ -1506,7 +1506,7 @@ icalcomponent* icalbdbsetiter_to_next(icalset *set, icalsetiter* i)
                     i->last_component = NULL;
                     icalrecur_iterator_free(i->ritr);
                     i->ritr = NULL;
-                    /* no more occurence, should go to get next component */
+                    /* no more occurrence, should go to get next component */
                     continue;
                 } else {
                     i->last_component = comp;
diff --git a/calendar/locales/en-US/chrome/calendar/calendar-recurrence-dialog.dtd b/calendar/locales/en-US/chrome/calendar/calendar-recurrence-dialog.dtd
index 93530e89594..e69de29bb2d 100644
--- a/calendar/locales/en-US/chrome/calendar/calendar-recurrence-dialog.dtd
+++ b/calendar/locales/en-US/chrome/calendar/calendar-recurrence-dialog.dtd
@@ -1,59 +0,0 @@
-<!-- ***** BEGIN LICENSE BLOCK *****
-   - Version: MPL 1.1/GPL 2.0/LGPL 2.1
-   -
-   - The contents of this file are subject to the Mozilla Public License Version
-   - 1.1 (the "License"); you may not use this file except in compliance with
-   - the License. You may obtain a copy of the License at
-   - http://www.mozilla.org/MPL/
-   -
-   - Software distributed under the License is distributed on an "AS IS" basis,
-   - WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
-   - for the specific language governing rights and limitations under the
-   - License.
-   -
-   - The Original Code is OEone Calendar Code, released October 31st, 2001.
-   -
-   - The Initial Developer of the Original Code is
-   - OEone Corporation.
-   - Portions created by the Initial Developer are Copyright (C) 2001
-   - the Initial Developer. All Rights Reserved.
-   -
-   - Contributor(s):
-   -   Cédric Corazza <cedric.corazza@wanadoo.fr>
-   -
-   - Alternatively, the contents of this file may be used under the terms of
-   - either the GNU General Public License Version 2 or later (the "GPL"), or
-   - the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
-   - in which case the provisions of the GPL or the LGPL are applicable instead
-   - of those above. If you wish to allow use of your version of this file only
-   - under the terms of either the GPL or the LGPL, and not to allow others to
-   - use your version of this file under the terms of the MPL, indicate your
-   - decision by deleting the provisions above and replace them with the notice
-   - and other provisions required by the LGPL or the GPL. If you do not delete
-   - the provisions above, a recipient may use your version of this file under
-   - the terms of any one of the MPL, the GPL or the LGPL.
-   -
-   - ***** END LICENSE BLOCK ***** -->
-
-<!ENTITY newevent.recurrence.occurs.label    "Occurs" >
-<!ENTITY newevent.recurrence.day.label       "daily" >
-<!ENTITY newevent.recurrence.week.label      "weekly" >
-<!ENTITY newevent.recurrence.month.label     "monthly" >
-<!ENTITY newevent.recurrence.year.label      "annually" >
-
-<!ENTITY newevent.recurrence.every.label     "Every:" >
-<!ENTITY repeat.units.days                   "Days" >
-<!ENTITY newevent.recurrence.weeks.label     "weeks on" >
-<!ENTITY newevent.recurrence.months.label    "months on the" >
-<!ENTITY repeat.units.years                  "Years" >
-
-<!ENTITY newevent.repeat.forever.label       "Repeat forever" >
-<!ENTITY newevent.repeat.for.label           "Repeat for" >
-<!ENTITY repeat.units.occurence.both         "occurrence(s)" >
-<!ENTITY newevent.repeat.until.label         "Repeat until" >
-
-<!-- Information messages -->
-<!ENTITY newevent.recurnumberoftimes.warning "You must specify the number of times to repeat.">
-<!ENTITY newevent.recurinterval.warning      "You must specify how often to repeat.">
-<!ENTITY newevent.recurrence.title           "Edit Recurrence" >
-<!ENTITY newevent.recurrence.lastday.label   "Last day of the month" >
diff --git a/calendar/prototypes/wcap/sun-calendar-event-dialog-recurrence-preview.xml b/calendar/prototypes/wcap/sun-calendar-event-dialog-recurrence-preview.xml
index fbacf65acf3..f0f81d3379d 100644
--- a/calendar/prototypes/wcap/sun-calendar-event-dialog-recurrence-preview.xml
+++ b/calendar/prototypes/wcap/sun-calendar-event-dialog-recurrence-preview.xml
@@ -233,7 +233,7 @@
                       var dates = aRecurrenceInfo.getOccurrenceDates(start, end, 0, {});
                       
                       // now run throgh all days of this month and set the
-                      // 'busy' attribute with respect to the occurence array.
+                      // 'busy' attribute with respect to the occurrence array.
                       var index = 0;
                       var occurrence = null;
                       if (index < dates.length) {
diff --git a/calendar/providers/gdata/components/calGoogleCalendar.js b/calendar/providers/gdata/components/calGoogleCalendar.js
index 02eaf760ed6..866466fd5bd 100644
--- a/calendar/providers/gdata/components/calGoogleCalendar.js
+++ b/calendar/providers/gdata/components/calGoogleCalendar.js
@@ -336,7 +336,7 @@ calGoogleCalendar.prototype = {
             }
 
             // Check if the item is an occurrence. Until bug 362650 is solved,
-            // there is no support for changing single ocurrences.
+            // there is no support for changing single occurrences.
             if (aOldItem.getProperty("X-GOOGLE-ITEM-IS-OCCURRENCE")) {
                 throw new Components.Exception("", Components.results.NS_ERROR_NOT_IMPLEMENTED);
             }
diff --git a/calendar/resources/content/mouseoverPreviews.js b/calendar/resources/content/mouseoverPreviews.js
index 21db4310a58..0f3d5e4aecd 100644
--- a/calendar/resources/content/mouseoverPreviews.js
+++ b/calendar/resources/content/mouseoverPreviews.js
@@ -465,9 +465,9 @@ function createTooltipHeaderDescription(text)
 }
 
 /**
- * If now is during an occurrence, return the ocurrence.
- * Else if now is before an ocurrence, return the next ocurrence.
- * Otherwise return the previous ocurrence.
+ * If now is during an occurrence, return the occurrence.
+ * Else if now is before an occurrence, return the next occurrence.
+ * Otherwise return the previous occurrence.
  */
 function getCurrentNextOrPreviousRecurrence(calendarEvent)
 {
diff --git a/calendar/test/homegrown/misc/synchronization.js b/calendar/test/homegrown/misc/synchronization.js
index 73a534c7db3..5bfded7ca63 100644
--- a/calendar/test/homegrown/misc/synchronization.js
+++ b/calendar/test/homegrown/misc/synchronization.js
@@ -42,7 +42,7 @@ var changeItems = [];
 
 // This will get the items from the calendars into the global arrays,
 // then call doSync()
-getCalandarItems();
+getCalendarItems();
 
 function doSync()
 {
@@ -128,7 +128,7 @@ function createEvent(aID, aTitle, aCal)
   aCal.addItem(event, emptyListener);
 }
 
-function getCalandarItems()
+function getCalendarItems()
 {
   var calendarsFinished = 0;