diff --git a/accessible/ipc/extension/mac/DocAccessiblePlatformExtChild.cpp b/accessible/ipc/extension/mac/DocAccessiblePlatformExtChild.cpp
index 8094eef03623..7e526b5bb2c4 100644
--- a/accessible/ipc/extension/mac/DocAccessiblePlatformExtChild.cpp
+++ b/accessible/ipc/extension/mac/DocAccessiblePlatformExtChild.cpp
@@ -169,6 +169,14 @@ mozilla::ipc::IPCResult DocAccessiblePlatformExtChild::RecvOffsetAtIndex(
 mozilla::ipc::IPCResult DocAccessiblePlatformExtChild::RecvRangeOfChild(
     const uint64_t& aID, const uint64_t& aChild, int32_t* aStartOffset,
     int32_t* aEndOffset) {
+  HyperTextAccessibleWrap* acc = IdToHyperTextAccessibleWrap(aID);
+  Accessible* child =
+      static_cast<DocAccessibleChild*>(Manager())->IdToAccessible(aChild);
+  if (!acc || !child) {
+    return IPC_OK();
+  }
+
+  acc->RangeOfChild(child, aStartOffset, aEndOffset);
   return IPC_OK();
 }
 
diff --git a/accessible/mac/GeckoTextMarker.h b/accessible/mac/GeckoTextMarker.h
index 46b613b02d39..bd0cd58ef1f5 100644
--- a/accessible/mac/GeckoTextMarker.h
+++ b/accessible/mac/GeckoTextMarker.h
@@ -74,6 +74,8 @@ class GeckoTextMarkerRange final {
   GeckoTextMarkerRange(AccessibleOrProxy aDoc,
                        AXTextMarkerRangeRef aTextMarkerRange);
 
+  explicit GeckoTextMarkerRange(const AccessibleOrProxy& aAccessible);
+
   id CreateAXTextMarkerRange();
 
   bool IsValid() const {
diff --git a/accessible/mac/GeckoTextMarker.mm b/accessible/mac/GeckoTextMarker.mm
index 7b410c0c574b..deb0c440cbbc 100644
--- a/accessible/mac/GeckoTextMarker.mm
+++ b/accessible/mac/GeckoTextMarker.mm
@@ -288,6 +288,21 @@ GeckoTextMarkerRange::GeckoTextMarkerRange(
   CFRelease(end_marker);
 }
 
+GeckoTextMarkerRange::GeckoTextMarkerRange(
+    const AccessibleOrProxy& aAccessible) {
+  mStart = GeckoTextMarker(aAccessible.Parent(), 0);
+  mEnd = GeckoTextMarker(aAccessible.Parent(), 0);
+  if (mStart.mContainer.IsProxy()) {
+    DocAccessibleParent* ipcDoc = mStart.mContainer.AsProxy()->Document();
+    Unused << ipcDoc->GetPlatformExtension()->SendRangeOfChild(
+        mStart.mContainer.AsProxy()->ID(), aAccessible.AsProxy()->ID(),
+        &mStart.mOffset, &mEnd.mOffset);
+  } else if (auto htWrap = mStart.ContainerAsHyperTextWrap()) {
+    htWrap->RangeOfChild(aAccessible.AsAccessible(), &mStart.mOffset,
+                         &mEnd.mOffset);
+  }
+}
+
 id GeckoTextMarkerRange::CreateAXTextMarkerRange() {
   AXTextMarkerRangeRef cf_text_marker_range =
       AXTextMarkerRangeCreate(kCFAllocatorDefault, mStart.CreateAXTextMarker(),
diff --git a/accessible/mac/HyperTextAccessibleWrap.h b/accessible/mac/HyperTextAccessibleWrap.h
index dccd735bab02..527523f9b407 100644
--- a/accessible/mac/HyperTextAccessibleWrap.h
+++ b/accessible/mac/HyperTextAccessibleWrap.h
@@ -46,6 +46,9 @@ class HyperTextAccessibleWrap : public HyperTextAccessible {
   void PreviousClusterAt(int32_t aOffset, HyperTextAccessible** aPrevContainer,
                          int32_t* aPrevOffset);
 
+  void RangeOfChild(Accessible* aChild, int32_t* aStartOffset,
+                    int32_t* aEndOffset);
+
  protected:
   ~HyperTextAccessibleWrap() {}
 
diff --git a/accessible/mac/HyperTextAccessibleWrap.mm b/accessible/mac/HyperTextAccessibleWrap.mm
index f98e10a4c382..8dee6f1989c9 100644
--- a/accessible/mac/HyperTextAccessibleWrap.mm
+++ b/accessible/mac/HyperTextAccessibleWrap.mm
@@ -351,6 +351,20 @@ void HyperTextAccessibleWrap::PreviousClusterAt(
   *aPrevOffset = prev.mOffset;
 }
 
+void HyperTextAccessibleWrap::RangeOfChild(Accessible* aChild,
+                                           int32_t* aStartOffset,
+                                           int32_t* aEndOffset) {
+  MOZ_ASSERT(aChild->Parent() == this);
+  *aStartOffset = *aEndOffset = -1;
+  int32_t index = GetIndexOf(aChild);
+  if (index != -1) {
+    *aStartOffset = GetChildOffset(index);
+    // If this is the last child index + 1 will return the total
+    // chracter count.
+    *aEndOffset = GetChildOffset(index + 1);
+  }
+}
+
 TextPoint HyperTextAccessibleWrap::FindTextPoint(
     int32_t aOffset, nsDirection aDirection, nsSelectionAmount aAmount,
     EWordMovementType aWordMovementType) {
diff --git a/accessible/mac/MOXAccessibleProtocol.h b/accessible/mac/MOXAccessibleProtocol.h
index ad68d0d6f2f8..6c6e9cd9c958 100644
--- a/accessible/mac/MOXAccessibleProtocol.h
+++ b/accessible/mac/MOXAccessibleProtocol.h
@@ -398,4 +398,7 @@
 // AXTextMarkerForIndex
 - (id _Nullable)moxTextMarkerForIndex:(NSNumber* _Nonnull)index;
 
+// AXTextMarkerRangeForUIElement
+- (id _Nullable)moxTextMarkerRangeForUIElement:(id _Nonnull)element;
+
 @end
diff --git a/accessible/mac/MOXTextMarkerDelegate.h b/accessible/mac/MOXTextMarkerDelegate.h
index 63ee5b83f879..fdb534c0c743 100644
--- a/accessible/mac/MOXTextMarkerDelegate.h
+++ b/accessible/mac/MOXTextMarkerDelegate.h
@@ -74,4 +74,7 @@
 // override
 - (NSValue*)moxBoundsForTextMarkerRange:(id)textMarkerRange;
 
+// override
+- (id)moxTextMarkerRangeForUIElement:(id)element;
+
 @end
diff --git a/accessible/mac/MOXTextMarkerDelegate.mm b/accessible/mac/MOXTextMarkerDelegate.mm
index 0aea2a95c75e..c0813be83812 100644
--- a/accessible/mac/MOXTextMarkerDelegate.mm
+++ b/accessible/mac/MOXTextMarkerDelegate.mm
@@ -243,4 +243,13 @@ static nsDataHashtable<nsUint64HashKey, MOXTextMarkerDelegate*> sDelegates;
   return geckoTextMarker.CreateAXTextMarker();
 }
 
+- (id)moxTextMarkerRangeForUIElement:(id)element {
+  if (![element isKindOfClass:[mozAccessible class]]) {
+    return nil;
+  }
+
+  GeckoTextMarkerRange range([element geckoAccessible]);
+  return range.CreateAXTextMarkerRange();
+}
+
 @end