--- a/content/html/content/src/nsHTMLOptGroupElement.cpp
+++ b/content/html/content/src/nsHTMLOptGroupElement.cpp
@@ -49,16 +49,19 @@ public:
   virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor);
 
   virtual nsEventStates IntrinsicState() const;
  
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
+  virtual nsresult AfterSetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
+                                const nsAttrValue* aValue, bool aNotify);
+
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   virtual bool IsDisabled() const {
     return HasAttr(kNameSpaceID_None, nsGkAtoms::disabled);
   }
 protected:
 
   /**
@@ -160,16 +163,36 @@ nsHTMLOptGroupElement::InsertChildAt(nsI
 void
 nsHTMLOptGroupElement::RemoveChildAt(PRUint32 aIndex, bool aNotify)
 {
   nsSafeOptionListMutation safeMutation(GetSelect(), this, nsnull, aIndex,
                                         aNotify);
   nsGenericHTMLElement::RemoveChildAt(aIndex, aNotify);
 }
 
+nsresult
+nsHTMLOptGroupElement::AfterSetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
+                                    const nsAttrValue* aValue, bool aNotify)
+{
+  if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::disabled) {
+    // All our children <option> have their :disabled state depending on our
+    // disabled attribute. We should make sure their state is updated.
+    for (nsIContent* child = nsINode::GetFirstChild(); child;
+         child = child->GetNextSibling()) {
+      if (child->IsHTML(nsGkAtoms::option)) {
+        // No need to call |IsElement()| because it's an HTML element.
+        child->AsElement()->UpdateState(true);
+      }
+    }
+  }
+
+  return nsGenericHTMLElement::AfterSetAttr(aNameSpaceID, aName, aValue,
+                                            aNotify);
+}
+
 nsEventStates
 nsHTMLOptGroupElement::IntrinsicState() const
 {
   nsEventStates state = nsGenericHTMLElement::IntrinsicState();
 
   if (HasAttr(kNameSpaceID_None, nsGkAtoms::disabled)) {
     state |= NS_EVENT_STATE_DISABLED;
     state &= ~NS_EVENT_STATE_ENABLED;

--- a/content/html/content/src/nsHTMLOptionElement.cpp
+++ b/content/html/content/src/nsHTMLOptionElement.cpp
@@ -272,33 +272,67 @@ nsHTMLOptionElement::GetText(nsAString& 
 }
 
 NS_IMETHODIMP
 nsHTMLOptionElement::SetText(const nsAString& aText)
 {
   return nsContentUtils::SetNodeTextContent(this, aText, true);
 }
 
+nsresult
+nsHTMLOptionElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
+                                nsIContent* aBindingParent,
+                                bool aCompileEventHandlers)
+{
+  nsresult rv = nsGenericHTMLElement::BindToTree(aDocument, aParent,
+                                                 aBindingParent,
+                                                 aCompileEventHandlers);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Our new parent might change :disabled/:enabled state.
+  UpdateState(false);
+
+  return NS_OK;
+}
+
+void
+nsHTMLOptionElement::UnbindFromTree(bool aDeep, bool aNullParent)
+{
+  nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
+
+  // Our previous parent could have been involved in :disabled/:enabled state.
+  UpdateState(false);
+}
+
 nsEventStates
 nsHTMLOptionElement::IntrinsicState() const
 {
   nsEventStates state = nsGenericHTMLElement::IntrinsicState();
   if (Selected()) {
     state |= NS_EVENT_STATE_CHECKED;
   }
   if (DefaultSelected()) {
     state |= NS_EVENT_STATE_DEFAULT;
   }
 
+  // An <option> is disabled if it has @disabled set or if it's <optgroup> has
+  // @disabled set.
   if (HasAttr(kNameSpaceID_None, nsGkAtoms::disabled)) {
     state |= NS_EVENT_STATE_DISABLED;
     state &= ~NS_EVENT_STATE_ENABLED;
   } else {
-    state &= ~NS_EVENT_STATE_DISABLED;
-    state |= NS_EVENT_STATE_ENABLED;
+    nsIContent* parent = GetParent();
+    if (parent && parent->IsHTML(nsGkAtoms::optgroup) &&
+        parent->HasAttr(kNameSpaceID_None, nsGkAtoms::disabled)) {
+      state |= NS_EVENT_STATE_DISABLED;
+      state &= ~NS_EVENT_STATE_ENABLED;
+    } else {
+      state &= ~NS_EVENT_STATE_DISABLED;
+      state |= NS_EVENT_STATE_ENABLED;
+    }
   }
 
   return state;
 }
 
 // Get the select content element that contains this option
 nsHTMLSelectElement*
 nsHTMLOptionElement::GetSelect()

--- a/content/html/content/src/nsHTMLOptionElement.h
+++ b/content/html/content/src/nsHTMLOptionElement.h
@@ -57,16 +57,22 @@ public:
                                               PRInt32 aModType) const;
 
   virtual nsresult BeforeSetAttr(PRInt32 aNamespaceID, nsIAtom* aName,
                                  const nsAttrValueOrString* aValue,
                                  bool aNotify);
 
   void SetSelectedInternal(bool aValue, bool aNotify);
 
+  virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
+                              nsIContent* aBindingParent,
+                              bool aCompileEventHandlers);
+  virtual void UnbindFromTree(bool aDeep = true,
+                              bool aNullParent = true);
+
   // nsIContent
   virtual nsEventStates IntrinsicState() const;
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   nsresult CopyInnerTo(nsGenericElement* aDest) const;
 
   virtual nsXPCClassInfo* GetClassInfo();

--- a/content/html/content/test/forms/Makefile.in
+++ b/content/html/content/test/forms/Makefile.in
@@ -34,13 +34,14 @@ include $(topsrcdir)/config/rules.mk
 		test_datalist_element.html \
 		test_form_attributes_reflection.html \
 		test_option_index_attribute.html \
 		test_progress_element.html \
 		test_form_attribute-1.html \
 		test_form_attribute-2.html \
 		test_form_attribute-3.html \
 		test_form_attribute-4.html \
+		test_option_disabled.html \
 		$(NULL)
 
 libs:: $(_TEST_FILES)
 	$(INSTALL) $(foreach f,$^,"$f") $(DEPTH)/_tests/testing/mochitest/tests/$(relativesrcdir)
 

new file mode 100644
--- /dev/null
+++ b/content/html/content/test/forms/test_option_disabled.html
@@ -0,0 +1,123 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=759666
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for HTMLOptionElement disabled attribute and pseudo-class</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=759666">Mozilla Bug 759666</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for HTMLOptionElement disabled attribute and pseudo-class **/
+
+var testCases = [
+  // Static checks.
+  { html: "<option></option>",
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<option disabled></option>",
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup><option></option></otpgroup>",
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup><option disabled></option></optgroup>",
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup disabled><option disabled></option></optgroup>",
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup disabled><option></option></optgroup>",
+    result: { attr: null, idl: false, pseudo: true } },
+  { html: "<optgroup><optgroup disabled><option></option></optgroup></optgroup>",
+    result: { attr: null, idl: false, pseudo: true } },
+  { html: "<optgroup disabled><optgroup><option></option></optgroup></optgroup>",
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><optgroup><option disabled></option></optgroup></optgroup>",
+    result: { attr: "", idl: true, pseudo: true } },
+
+  // Dynamic checks: changing disable value.
+  { html: "<option></option>",
+    modifier: function(c) { c.querySelector('option').disabled = true; },
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<option disabled></option>",
+    modifier: function(c) { c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup><option></option></otpgroup>",
+    modifier: function(c) { c.querySelector('optgroup').disabled = true; },
+    result: { attr: null, idl: false, pseudo: true } },
+  { html: "<optgroup><option disabled></option></optgroup>",
+    modifier: function(c) { c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><option disabled></option></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup').disabled = false; },
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup disabled><option disabled></option></optgroup>",
+    modifier: function(c) { c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: true } },
+  { html: "<optgroup disabled><option disabled></option></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup').disabled = c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><option></option></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup><optgroup disabled><option></option></optgroup></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup[disabled]').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><optgroup><option></option></optgroup></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup[disabled]').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><optgroup><option disabled></option></optgroup></optgroup>",
+    modifier: function(c) { c.querySelector('optgroup').disabled = false; },
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup disabled><optgroup><option disabled></option></optgroup></optgroup>",
+    modifier: function(c) { c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup disabled><optgroup><option disabled></option></optgroup></optgroup>",
+    modifier: function(c) { c.querySelector('option').disabled = c.querySelector('option').disabled = false; },
+    result: { attr: null, idl: false, pseudo: false } },
+
+  // Dynamic checks: moving option element.
+  { html: "<optgroup id='a'><option></option></optgroup><optgroup id='b'></optgroup>",
+    modifier: function(c) { c.querySelector('#b').appendChild(c.querySelector('option')); },
+    result: { attr: null, idl: false, pseudo: false } },
+  { html: "<optgroup id='a'><option disabled></option></optgroup><optgroup id='b'></optgroup>",
+    modifier: function(c) { c.querySelector('#b').appendChild(c.querySelector('option')); },
+    result: { attr: "", idl: true, pseudo: true } },
+  { html: "<optgroup id='a'><option></option></optgroup><optgroup disabled id='b'></optgroup>",
+    modifier: function(c) { c.querySelector('#b').appendChild(c.querySelector('option')); },
+    result: { attr: null, idl: false, pseudo: true } },
+  { html: "<optgroup disabled id='a'><option></option></optgroup><optgroup id='b'></optgroup>",
+    modifier: function(c) { c.querySelector('#b').appendChild(c.querySelector('option')); },
+    result: { attr: null, idl: false, pseudo: false } },
+];
+
+var content = document.getElementById('content');
+
+testCases.forEach(function(testCase) {
+  var result = testCase.result;
+
+  content.innerHTML = testCase.html;
+
+  if (testCase.modifier !== undefined) {
+    testCase.modifier(content);
+  }
+
+  var option = content.querySelector('option');
+  is(option.getAttribute('disabled'), result.attr, "disabled content attribute value should be " + result.attr);
+  is(option.disabled, result.idl, "disabled idl attribute value should be " + result.idl);
+  is(option.mozMatchesSelector(":disabled"), result.pseudo, ":disabled state should be " + result.pseudo);
+  is(option.mozMatchesSelector(":enabled"), !result.pseudo, ":enabled state should be " + !result.pseudo);
+
+  content.innerHTML = "";
+});
+
+</script>
+</pre>
+</body>
+</html>