diff --git a/mozilla/calendar/install.js b/mozilla/calendar/install.js
index 55b5af0379a..a2db354d2f6 100644
--- a/mozilla/calendar/install.js
+++ b/mozilla/calendar/install.js
@@ -26,7 +26,7 @@ if ( err == SUCCESS ) {
    err = performInstall();
   
    if ( err == SUCCESS ) {
-      alert("The Mozilla Calendar has been succesfully installed. \n"
+      alert("The Mozilla Calendar has been successfully installed. \n"
       +"Please restart your browser to continue.");
    }
    else if( err == "999" )
diff --git a/mozilla/calendar/linux/install.js b/mozilla/calendar/linux/install.js
index 2a29c32939c..807cb3a100a 100644
--- a/mozilla/calendar/linux/install.js
+++ b/mozilla/calendar/linux/install.js
@@ -49,7 +49,7 @@ if ( err == SUCCESS ) {
    err = performInstall();
   
    if ( err == SUCCESS || err == 999 ) {
-      alert("The Mozilla Calendar has been succesfully installed. \n"
+      alert("The Mozilla Calendar has been successfully installed. \n"
       +"Please restart your application to continue.");
    } else { 
     alert("performInstall() failed. \n"
diff --git a/mozilla/calendar/windows/install.js b/mozilla/calendar/windows/install.js
index 2a29c32939c..807cb3a100a 100644
--- a/mozilla/calendar/windows/install.js
+++ b/mozilla/calendar/windows/install.js
@@ -49,7 +49,7 @@ if ( err == SUCCESS ) {
    err = performInstall();
   
    if ( err == SUCCESS || err == 999 ) {
-      alert("The Mozilla Calendar has been succesfully installed. \n"
+      alert("The Mozilla Calendar has been successfully installed. \n"
       +"Please restart your application to continue.");
    } else { 
     alert("performInstall() failed. \n"