diff --git a/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.cpp b/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.cpp
index 3a792bc70e49..653fcef439eb 100644
--- a/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.cpp
+++ b/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.cpp
@@ -236,7 +236,7 @@ txStandaloneXSLTProcessor::transform(txXPathNode& aSource,
 /**
  * Parses the XML Stylesheet PIs associated with the
  * given XML document. If a stylesheet PIs is found with type="text/xsl"
- * or type="text/xml" the href psuedo attribute value will be appended to
+ * or type="text/xml" the href pseudo attribute value will be appended to
  * the given href argument. If multiple text/xsl stylesheet PIs
  * are found, the first one is used.
  */
diff --git a/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.h b/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.h
index 2b7444570eb9..e70baa7d941b 100644
--- a/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.h
+++ b/extensions/transformiix/source/xslt/txStandaloneXSLTProcessor.h
@@ -139,14 +139,14 @@ protected:
     /**
      * Parses all XML Stylesheet PIs associated with the
      * given XML document. If any stylesheet PIs are found with
-     * type="text/xsl" the href psuedo attribute value will be
+     * type="text/xsl" the href pseudo attribute value will be
      * added to the given href argument. If multiple text/xsl stylesheet PIs
      * are found, the one closest to the end of the document is used.
      */
     static void getHrefFromStylesheetPI(Document& xmlDocument, nsAString& href);
 
     /**
-     * Parses the contents of data, returns the type and href psuedo attributes
+     * Parses the contents of data, returns the type and href pseudo attributes
      */
     static void parseStylesheetPI(const nsAFlatString& data,
                                   nsAString& type,
diff --git a/js/src/jsregexp.c b/js/src/jsregexp.c
index e362d060a22e..5c60b958c990 100644
--- a/js/src/jsregexp.c
+++ b/js/src/jsregexp.c
@@ -3100,7 +3100,7 @@ js_ExecuteRegExp(JSContext *cx, JSRegExp *re, JSString *str, size_t *indexp,
         /*
          * JS1.2 emulated Perl4.0.1.8 (patch level 36) for global regexps used
          * in scalar contexts, and unintentionally for the string.match "list"
-         * psuedo-context.  On "hi there bye", the following would result:
+         * pseudo-context.  On "hi there bye", the following would result:
          *
          * Language     while(/ /g){print("$`");}   s/ /$`/g
          * perl4.036    "hi", "there"               "hihitherehi therebye"
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index 317f717a66a2..c9004b927185 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -3634,7 +3634,7 @@ nsCSSFrameConstructor::TableProcessChild(nsIPresShell*            aPresShell,
     {
 
       // if <form>'s parent is <tr>/<table>/<tbody>/<thead>/<tfoot> in html,
-      // NOT create psuedoframe for it.
+      // NOT create pseudoframe for it.
       // see bug 159359
       nsINodeInfo *childNodeInfo = aChildContent->GetNodeInfo();
       // Sometimes aChildContent is a #text node.  In those cases it
@@ -4596,7 +4596,7 @@ nsCSSFrameConstructor::ConstructSelectFrame(nsIPresShell*        aPresShell,
          // Notify combobox that it should use the listbox as it's popup
       comboBox->SetDropDown(listFrame);
 
-        // Resolve psuedo element style for the dropdown list 
+        // Resolve pseudo element style for the dropdown list 
       nsRefPtr<nsStyleContext> listStyle;
       listStyle = aPresShell->StyleSet()->ResolvePseudoStyleFor(aContent, 
                                                                 nsCSSAnonBoxes::dropDownList, 
diff --git a/layout/forms/nsComboboxControlFrame.cpp b/layout/forms/nsComboboxControlFrame.cpp
index 64fa21a6761d..67bde91c534a 100644
--- a/layout/forms/nsComboboxControlFrame.cpp
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -109,7 +109,7 @@
 // The drop-down list does not explicitly set capture when it is in the drop-down mode.
 
 
-//XXX: This is temporary. It simulates psuedo states by using a attribute selector on 
+//XXX: This is temporary. It simulates pseudo states by using a attribute selector on 
 
 const PRInt32 kSizeNotSet = -1;
 
diff --git a/layout/tables/nsTableOuterFrame.h b/layout/tables/nsTableOuterFrame.h
index 3757f141efe5..897560ac1951 100644
--- a/layout/tables/nsTableOuterFrame.h
+++ b/layout/tables/nsTableOuterFrame.h
@@ -69,7 +69,7 @@ protected:
 /**
  * main frame for an nsTable content object, 
  * the nsTableOuterFrame contains 0 or one caption frame, and a nsTableFrame
- * psuedo-frame (referred to as the "inner frame').
+ * pseudo-frame (referred to as the "inner frame').
  */
 class nsTableOuterFrame : public nsHTMLContainerFrame, public nsITableLayout
 {
diff --git a/mailnews/imap/src/nsImapProtocol.cpp b/mailnews/imap/src/nsImapProtocol.cpp
index ea3a8d18a51a..100ca3ee95e7 100644
--- a/mailnews/imap/src/nsImapProtocol.cpp
+++ b/mailnews/imap/src/nsImapProtocol.cpp
@@ -3210,7 +3210,7 @@ nsImapProtocol::PostLineDownLoadEvent(msg_line_info *downloadLineDontDelete)
       downloadLineDontDelete->uidOfMessage);
     }
   }
-  // ***** We need to handle the psuedo interrupt here *****
+  // ***** We need to handle the pseudo interrupt here *****
 }
 
 // well, this is what the old code used to look like to handle a line seen by the parser.
diff --git a/xpcom/io/nsFastLoadFile.cpp b/xpcom/io/nsFastLoadFile.cpp
index 3b96fa5f798f..1f2030799e41 100644
--- a/xpcom/io/nsFastLoadFile.cpp
+++ b/xpcom/io/nsFastLoadFile.cpp
@@ -2073,7 +2073,7 @@ nsFastLoadFileWriter::Close()
     return mOutputStream->Close();
 }
 
-// Psuedo-tag used as flag between WriteSingleRefObject and WriteObjectCommon.
+// Pseudo-tag used as flag between WriteSingleRefObject and WriteObjectCommon.
 #define MFL_SINGLE_REF_PSEUDO_TAG       PR_BIT(MFL_OBJECT_TAG_BITS)
 
 nsresult