diff --git a/accessible/ipc/win/ProxyAccessible.cpp b/accessible/ipc/win/ProxyAccessible.cpp
index 1bef1fc3a652..d6aa13cc2b2b 100644
--- a/accessible/ipc/win/ProxyAccessible.cpp
+++ b/accessible/ipc/win/ProxyAccessible.cpp
@@ -6,6 +6,7 @@
 
 #include "Accessible2.h"
 #include "ProxyAccessible.h"
+#include "ia2AccessibleRelation.h"
 #include "ia2AccessibleValue.h"
 #include "IGeckoCustom.h"
 #include "mozilla/a11y/DocAccessibleParent.h"
@@ -80,6 +81,12 @@ struct InterfaceIID<IGeckoCustom>
   static REFIID Value() { return IID_IGeckoCustom; }
 };
 
+template<>
+struct InterfaceIID<IAccessible2_2>
+{
+  static REFIID Value() { return IID_IAccessible2_2; }
+};
+
 /**
  * Get the COM proxy for this proxy accessible and QueryInterface it with the
  * correct IID
@@ -363,6 +370,44 @@ ProxyAccessible::Attributes(nsTArray<Attribute>* aAttrs) const
                                aAttrs);
 }
 
+nsTArray<ProxyAccessible*>
+ProxyAccessible::RelationByType(RelationType aType) const
+{
+  RefPtr<IAccessible2_2> acc = QueryInterface<IAccessible2_2>(this);
+  if (!acc) {
+    nsTArray<ProxyAccessible*>();
+  }
+
+  _bstr_t relationType;
+  for (uint32_t idx = 0; idx < ArrayLength(sRelationTypePairs); idx++) {
+    if (aType == sRelationTypePairs[idx].first) {
+      relationType = sRelationTypePairs[idx].second;
+      break;
+    }
+  }
+
+  if (!relationType) {
+    nsTArray<ProxyAccessible*>();
+  }
+
+  IUnknown** targets;
+  long nTargets = 0;
+  HRESULT hr = acc->get_relationTargetsOfType(relationType, 0, &targets, &nTargets);
+  if (FAILED(hr)) {
+    nsTArray<ProxyAccessible*>();
+  }
+
+  nsTArray<ProxyAccessible*> proxies;
+  for (long idx = 0; idx < nTargets; idx++) {
+    IUnknown* target = targets[idx];
+    proxies.AppendElement(GetProxyFor(Document(), target));
+    target->Release();
+  }
+  CoTaskMemFree(targets);
+
+  return Move(proxies);
+}
+
 double
 ProxyAccessible::CurValue()
 {
diff --git a/accessible/tests/browser/e10s/browser.ini b/accessible/tests/browser/e10s/browser.ini
index 0b7b5adad1dd..79a62c996575 100644
--- a/accessible/tests/browser/e10s/browser.ini
+++ b/accessible/tests/browser/e10s/browser.ini
@@ -21,7 +21,7 @@ skip-if = e10s && os == 'win' && os_version == '5.1'
 [browser_caching_name.js]
 skip-if = e10s && os == 'win' && os_version == '5.1'
 [browser_caching_relations.js]
-skip-if = e10s && os == 'win' # Bug 1288839
+skip-if = e10s && os == 'win' && os_version == '5.1'
 [browser_caching_states.js]
 skip-if = e10s && os == 'win' && os_version == '5.1'
 [browser_caching_value.js]
diff --git a/accessible/xpcom/xpcAccessible.cpp b/accessible/xpcom/xpcAccessible.cpp
index 10204ae7b270..dede700d19d6 100644
--- a/accessible/xpcom/xpcAccessible.cpp
+++ b/accessible/xpcom/xpcAccessible.cpp
@@ -504,16 +504,12 @@ xpcAccessible::GetRelationByType(uint32_t aType,
     return NS_OK;
   }
 
-#if defined(XP_WIN)
-  return NS_ERROR_NOT_IMPLEMENTED;
-#else
   ProxyAccessible* proxy = IntlGeneric().AsProxy();
   nsTArray<ProxyAccessible*> targets =
     proxy->RelationByType(static_cast<RelationType>(aType));
   NS_ADDREF(*aRelation = new nsAccessibleRelation(aType, &targets));
 
   return NS_OK;
-#endif
 }
 
 NS_IMETHODIMP