--- a/layout/base/nsCSSRendering.cpp
+++ b/layout/base/nsCSSRendering.cpp
@@ -3108,17 +3108,23 @@ nsCSSRendering::ComputeImageLayerPositio
     bgPositioningArea = nsRect(
       scrollableFrame->GetScrolledFrame()->GetPosition()
         // For the dir=rtl case:
         + scrollableFrame->GetScrollRange().TopLeft(),
       scrollableFrame->GetScrolledRect().Size());
     // The ScrolledRect’s size does not include the borders or scrollbars,
     // reverse the handling of background-origin
     // compared to the common case below.
-    if (aLayer.mOrigin == NS_STYLE_IMAGELAYER_ORIGIN_BORDER) {
+    if (aLayer.mOrigin == NS_STYLE_IMAGELAYER_ORIGIN_MARGIN) {
+      nsMargin margin = geometryFrame->GetUsedMargin();
+      margin.ApplySkipSides(geometryFrame->GetSkipSides());
+      bgPositioningArea.Inflate(margin);
+      bgPositioningArea.Inflate(scrollableFrame->GetActualScrollbarSizes());
+    }
+    else if (aLayer.mOrigin == NS_STYLE_IMAGELAYER_ORIGIN_BORDER) {
       nsMargin border = geometryFrame->GetUsedBorder();
       border.ApplySkipSides(geometryFrame->GetSkipSides());
       bgPositioningArea.Inflate(border);
       bgPositioningArea.Inflate(scrollableFrame->GetActualScrollbarSizes());
     } else if (aLayer.mOrigin != NS_STYLE_IMAGELAYER_ORIGIN_PADDING) {
       nsMargin padding = geometryFrame->GetUsedPadding();
       padding.ApplySkipSides(geometryFrame->GetSkipSides());
       bgPositioningArea.Deflate(padding);
@@ -3139,17 +3145,20 @@ nsCSSRendering::ComputeImageLayerPositio
       bgPositioningArea = geometryFrame->GetRect();
     }
   } else {
     bgPositioningArea = nsRect(nsPoint(0,0), aBorderArea.Size());
   }
 
   // Background images are tiled over the 'background-clip' area
   // but the origin of the tiling is based on the 'background-origin' area
-  if (aLayer.mOrigin != NS_STYLE_IMAGELAYER_ORIGIN_BORDER && geometryFrame) {
+  if (aLayer.mOrigin == NS_STYLE_IMAGELAYER_ORIGIN_MARGIN) {
+    nsMargin margin = geometryFrame->GetUsedMargin();
+    bgPositioningArea.Inflate(margin);
+  } else if (aLayer.mOrigin != NS_STYLE_IMAGELAYER_ORIGIN_BORDER && geometryFrame) {
     nsMargin border = geometryFrame->GetUsedBorder();
     if (aLayer.mOrigin != NS_STYLE_IMAGELAYER_ORIGIN_PADDING) {
       border += geometryFrame->GetUsedPadding();
       NS_ASSERTION(aLayer.mOrigin == NS_STYLE_IMAGELAYER_ORIGIN_CONTENT,
                    "unknown background-origin value");
     }
     bgPositioningArea.Deflate(border);
   }

--- a/layout/style/nsCSSProps.cpp
+++ b/layout/style/nsCSSProps.cpp
@@ -892,16 +892,17 @@ static_assert(NS_STYLE_IMAGELAYER_CLIP_B
               NS_STYLE_IMAGELAYER_CLIP_CONTENT == NS_STYLE_IMAGELAYER_ORIGIN_CONTENT,
               "Except background-clip:text, all {background,mask}-clip and "
               "{background,mask}-origin style constants must agree");
 
 const KTableEntry nsCSSProps::kImageLayerOriginKTable[] = {
   { eCSSKeyword_border_box, NS_STYLE_IMAGELAYER_ORIGIN_BORDER },
   { eCSSKeyword_padding_box, NS_STYLE_IMAGELAYER_ORIGIN_PADDING },
   { eCSSKeyword_content_box, NS_STYLE_IMAGELAYER_ORIGIN_CONTENT },
+  { eCSSKeyword_margin_box, NS_STYLE_IMAGELAYER_ORIGIN_MARGIN },
   { eCSSKeyword_UNKNOWN, -1 }
 };
 
 KTableEntry nsCSSProps::kBackgroundClipKTable[] = {
   { eCSSKeyword_border_box, NS_STYLE_IMAGELAYER_CLIP_BORDER },
   { eCSSKeyword_padding_box, NS_STYLE_IMAGELAYER_CLIP_PADDING },
   { eCSSKeyword_content_box, NS_STYLE_IMAGELAYER_CLIP_CONTENT },
   // The next entry is controlled by the layout.css.background-clip-text.enabled

--- a/layout/style/nsStyleConsts.h
+++ b/layout/style/nsStyleConsts.h
@@ -266,31 +266,33 @@ enum class FillMode : uint32_t;
 #define NS_STYLE_IMAGELAYER_ATTACHMENT_FIXED         1
 #define NS_STYLE_IMAGELAYER_ATTACHMENT_LOCAL         2
 
 // See nsStyleImageLayers
 // Code depends on these constants having the same values as IMAGELAYER_ORIGIN_*
 #define NS_STYLE_IMAGELAYER_CLIP_BORDER              0
 #define NS_STYLE_IMAGELAYER_CLIP_PADDING             1
 #define NS_STYLE_IMAGELAYER_CLIP_CONTENT             2
+#define NS_STYLE_IMAGELAYER_CLIP_MARGIN              3
 // One extra constant which does not exist in IMAGELAYER_ORIGIN_*
-#define NS_STYLE_IMAGELAYER_CLIP_TEXT                3
+#define NS_STYLE_IMAGELAYER_CLIP_TEXT                4
 
 // A magic value that we use for our "pretend that background-clip is
 // 'padding' when we have a solid border" optimization.  This isn't
 // actually equal to NS_STYLE_IMAGELAYER_CLIP_PADDING because using that
 // causes antialiasing seams between the background and border.  This
 // is a backend-only value.
 #define NS_STYLE_IMAGELAYER_CLIP_MOZ_ALMOST_PADDING  127
 
 // See nsStyleImageLayers
 // Code depends on these constants having the same values as BG_CLIP_*
 #define NS_STYLE_IMAGELAYER_ORIGIN_BORDER            0
 #define NS_STYLE_IMAGELAYER_ORIGIN_PADDING           1
 #define NS_STYLE_IMAGELAYER_ORIGIN_CONTENT           2
+#define NS_STYLE_IMAGELAYER_ORIGIN_MARGIN            3
 
 // See nsStyleImageLayers
 // The parser code depends on |ing these values together.
 #define NS_STYLE_IMAGELAYER_POSITION_CENTER          (1<<0)
 #define NS_STYLE_IMAGELAYER_POSITION_TOP             (1<<1)
 #define NS_STYLE_IMAGELAYER_POSITION_BOTTOM          (1<<2)
 #define NS_STYLE_IMAGELAYER_POSITION_LEFT            (1<<3)
 #define NS_STYLE_IMAGELAYER_POSITION_RIGHT           (1<<4)