--- a/accessible/src/base/nsARIAMap.cpp
+++ b/accessible/src/base/nsARIAMap.cpp
@@ -674,17 +674,17 @@ nsAttributeCharacteristics nsARIAMap::gW
   {&nsGkAtoms::aria_controls,          ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {&nsGkAtoms::aria_describedby,       ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {&nsGkAtoms::aria_disabled,          ATTR_BYPASSOBJ | ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_dropeffect,                         ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_expanded,          ATTR_BYPASSOBJ | ATTR_VALTOKEN               },
   {&nsGkAtoms::aria_flowto,            ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {&nsGkAtoms::aria_grabbed,                            ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_haspopup,          ATTR_BYPASSOBJ | ATTR_VALTOKEN | ATTR_GLOBAL },
-  {&nsGkAtoms::aria_hidden,                             ATTR_VALTOKEN | ATTR_GLOBAL },/* always expose obj attr */
+  {&nsGkAtoms::aria_hidden,   ATTR_BYPASSOBJ_IF_FALSE | ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_invalid,           ATTR_BYPASSOBJ | ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_label,             ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {&nsGkAtoms::aria_labelledby,        ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {&nsGkAtoms::aria_level,             ATTR_BYPASSOBJ                               }, /* handled via groupPosition */
   {&nsGkAtoms::aria_live,                               ATTR_VALTOKEN | ATTR_GLOBAL },
   {&nsGkAtoms::aria_multiline,         ATTR_BYPASSOBJ | ATTR_VALTOKEN               },
   {&nsGkAtoms::aria_multiselectable,   ATTR_BYPASSOBJ | ATTR_VALTOKEN               },
   {&nsGkAtoms::aria_owns,              ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
@@ -771,16 +771,22 @@ AttrIterator::Next(nsAString& aAttrName,
       uint8_t attrFlags = nsAccUtils::GetAttributeCharacteristics(attrAtom);
       if (attrFlags & ATTR_BYPASSOBJ)
         continue; // No need to handle exposing as obj attribute here
 
       if ((attrFlags & ATTR_VALTOKEN) &&
            !nsAccUtils::HasDefinedARIAToken(mContent, attrAtom))
         continue; // only expose token based attributes if they are defined
 
+      if ((attrFlags & ATTR_BYPASSOBJ_IF_FALSE) &&
+          mContent->AttrValueIs(kNameSpaceID_None, attrAtom,
+                                nsGkAtoms::_false, eCaseMatters)) {
+        continue; // only expose token based attribute if value is not 'false'.
+      }
+
       nsAutoString value;
       if (mContent->GetAttr(kNameSpaceID_None, attrAtom, value)) {
         aAttrName.Assign(Substring(attrStr, 5));
         aAttrValue.Assign(value);
         return true;
       }
     }
   }

--- a/accessible/src/base/nsARIAMap.h
+++ b/accessible/src/base/nsARIAMap.h
@@ -93,28 +93,29 @@ const bool kUseNativeRole = false;
 
 /**
  * This mask indicates the attribute should not be exposed as an object
  * attribute via the catch-all logic in Accessible::Attributes().
  * This means it either isn't mean't to be exposed as an object attribute, or
  * that it should, but is already handled in other code.
  */
 const uint8_t ATTR_BYPASSOBJ = 0x1 << 0;
+const uint8_t ATTR_BYPASSOBJ_IF_FALSE = 0x1 << 1;
 
 /**
  * This mask indicates the attribute is expected to have an NMTOKEN or bool value.
  * (See for example usage in Accessible::Attributes())
  */
-const uint8_t ATTR_VALTOKEN = 0x1 << 1;
+const uint8_t ATTR_VALTOKEN = 0x1 << 2;
 
 /**
  * Indicate the attribute is global state or property (refer to
  * http://www.w3.org/TR/wai-aria/states_and_properties#global_states).
  */
-const uint8_t ATTR_GLOBAL = 0x1 << 2;
+const uint8_t ATTR_GLOBAL = 0x1 << 3;
 
 /**
  * Small footprint storage of persistent aria attribute characteristics.
  */
 struct nsAttributeCharacteristics
 {
   nsIAtom** attributeName;
   const uint8_t characteristics;

--- a/accessible/tests/mochitest/attributes/test_obj.html
+++ b/accessible/tests/mochitest/attributes/test_obj.html
@@ -28,16 +28,17 @@ https://bugzilla.mozilla.org/show_bug.cg
       testAttrs("checkedCheckbox", {"checkable" : "true"}, true); 
       testAttrs("checkedMenuitem", {"checkable" : "true"}, true); 
       testAttrs("checkedOption", {"checkable" : "true"}, true); 
       testAttrs("checkedRadio", {"checkable" : "true"}, true); 
       testAttrs("checkedTreeitem", {"checkable" : "true"}, true); 
       testAttrs("dropeffect", {"dropeffect" : "copy"}, true);
       testAttrs("grabbed", {"grabbed" : "true"}, true);
       testAttrs("hidden", {"hidden" : "true"}, true);
+      testAbsentAttrs("hidden_false", { "hidden": "false" });
       testAttrs("sortAscending", {"sort" : "ascending"}, true);
       testAttrs("sortDescending", {"sort" : "descending"}, true);
       testAttrs("sortNone", {"sort" : "none"}, true);
       testAttrs("sortOther", {"sort" : "other"}, true);
 
       // inherited attributes by subdocuments
       var subdoc = getAccessible("iframe").firstChild;
       testAttrs(subdoc, {"busy" : "true"}, true);
@@ -157,16 +158,21 @@ https://bugzilla.mozilla.org/show_bug.cg
      title="Expand support for nsIAccessibleEvent::OBJECT_ATTRIBUTE_CHANGE">
     Mozilla Bug 563862
   </a>
   <a target="_blank"
      href="https://bugzilla.mozilla.org/show_bug.cgi?id=819303"
      title="crash in nsTextEquivUtils::AppendTextEquivFromTextContent">
     Mozilla Bug 819303
   </a>
+  <a target="_blank"
+     href="https://bugzilla.mozilla.org/show_bug.cgi?id=838407"
+     title="aria-hidden false value shouldn't be exposed via object attributes">
+    Mozilla Bug 838407
+  </a>
   <p id="display"></p>
   <div id="content" style="display: none"></div>
   <pre id="test">
   </pre>
 
   <!-- aria -->
   <div id="atomic" aria-atomic="true"></div>
   <div id="autocomplete" role="textbox" aria-autocomplete="true"></div>
@@ -174,16 +180,17 @@ https://bugzilla.mozilla.org/show_bug.cg
   <div id="checkedCheckbox" role="checkbox" aria-checked="true"></div>
   <div id="checkedMenuitem" role="menuitem" aria-checked="true"></div>
   <div id="checkedOption" role="option" aria-checked="true"></div>
   <div id="checkedRadio" role="radio" aria-checked="true"></div>
   <div id="checkedTreeitem" role="treeitem" aria-checked="true"></div>
   <div id="dropeffect" aria-dropeffect="copy"></div>
   <div id="grabbed" aria-grabbed="true"></div>
   <div id="hidden" aria-hidden="true"></div>
+  <div id="hidden_false" aria-hidden="false"></div>
   <div id="sortAscending" role="columnheader" aria-sort="ascending"></div>
   <div id="sortDescending" role="columnheader" aria-sort="descending"></div>
   <div id="sortNone" role="columnheader" aria-sort="none"></div>
   <div id="sortOther" role="columnheader" aria-sort="other"></div>
 
   <!-- inherited from iframe -->
   <iframe id="iframe" src="data:text/html,<html><body></body></html>"
           aria-busy="true"></iframe>