diff --git a/clients/window.c b/clients/window.c
index 97cce1a4..91c1ea06 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -3937,6 +3937,27 @@ window_sync_transient_for(struct window *window)
 	xdg_surface_set_transient_for(window->xdg_surface, parent_surface);
 }
 
+static void
+window_sync_margin(struct window *window)
+{
+	int margin;
+
+	if (!window->xdg_surface)
+		return;
+
+	if (!window->frame)
+		return;
+
+	margin = frame_get_shadow_margin(window->frame->frame);
+
+	/* Shadow size is the same on every side. */
+	xdg_surface_set_margin(window->xdg_surface,
+				     margin,
+				     margin,
+				     margin,
+				     margin);
+}
+
 static void
 window_flush(struct window *window)
 {
@@ -3953,6 +3974,7 @@ window_flush(struct window *window)
 						 &xdg_surface_listener, window);
 
 			window_sync_transient_for(window);
+			window_sync_margin(window);
 		}
 	}
 
diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index b9b49cb5..a73e8e02 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -3171,6 +3171,18 @@ xdg_surface_pong(struct wl_client *client,
 	surface_pong(shsurf, serial);
 }
 
+static void
+xdg_surface_set_margin(struct wl_client *client,
+			     struct wl_resource *resource,
+			     int32_t left,
+			     int32_t right,
+			     int32_t top,
+			     int32_t bottom)
+{
+	/* Do nothing, Weston doesn't try to constrain or place
+	 * surfaces in any special manner... */
+}
+
 static void
 xdg_surface_set_app_id(struct wl_client *client,
 		       struct wl_resource *resource,
@@ -3309,6 +3321,7 @@ xdg_surface_unset_maximized(struct wl_client *client,
 static const struct xdg_surface_interface xdg_surface_implementation = {
 	xdg_surface_destroy,
 	xdg_surface_set_transient_for,
+	xdg_surface_set_margin,
 	xdg_surface_set_title,
 	xdg_surface_set_app_id,
 	xdg_surface_pong,
diff --git a/protocol/xdg-shell.xml b/protocol/xdg-shell.xml
index 5c21f4eb..f0d04aa3 100644
--- a/protocol/xdg-shell.xml
+++ b/protocol/xdg-shell.xml
@@ -124,6 +124,32 @@
       <arg name="parent" type="object" interface="wl_surface" allow-null="true"/>
     </request>
 
+    <request name="set_margin">
+      <description summary="set the visible frame boundaries">
+        This tells the compositor what the visible size of the window
+        should be, so it can use it to determine what borders to use for
+        constrainment and alignment.
+
+        CSD often has invisible areas for decoration purposes, like drop
+        shadows. These "shadow" drawings need to be subtracted out of the
+        normal boundaries of the window when computing where to place
+        windows (e.g. to set this window so it's centered on top of another,
+        or to put it to the left or right of the screen.)
+
+        This value should change as little as possible at runtime, to
+        prevent flicker.
+
+        This value is also ignored when the window is maximized or
+        fullscreen, and assumed to be 0.
+
+        If never called, this value is assumed to be 0.
+      </description>
+      <arg name="left_margin" type="int"/>
+      <arg name="right_margin" type="int"/>
+      <arg name="top_margin" type="int"/>
+      <arg name="bottom_margin" type="int"/>
+    </request>
+
     <request name="set_title">
       <description summary="set surface title">
 	Set a short title for the surface.
diff --git a/shared/cairo-util.h b/shared/cairo-util.h
index 7bcbc296..4493b0d9 100644
--- a/shared/cairo-util.h
+++ b/shared/cairo-util.h
@@ -165,6 +165,9 @@ void
 frame_opaque_rect(struct frame *frame, int32_t *x, int32_t *y,
 		  int32_t *width, int32_t *height);
 
+int
+frame_get_shadow_margin(struct frame *frame);
+
 uint32_t
 frame_status(struct frame *frame);
 
diff --git a/shared/frame.c b/shared/frame.c
index a039d157..35e6b65e 100644
--- a/shared/frame.c
+++ b/shared/frame.c
@@ -578,6 +578,14 @@ frame_opaque_rect(struct frame *frame, int32_t *x, int32_t *y,
 		*height = frame->height - frame->opaque_margin * 2;
 }
 
+int
+frame_get_shadow_margin(struct frame *frame)
+{
+	frame_refresh_geometry(frame);
+
+	return frame->shadow_margin;
+}
+
 uint32_t
 frame_status(struct frame *frame)
 {