diff --git a/testing/marionette/action.js b/testing/marionette/action.js
index 11f196b09280..22a77019ed95 100644
--- a/testing/marionette/action.js
+++ b/testing/marionette/action.js
@@ -1213,6 +1213,15 @@ function dispatchPointerDown(a, inputState, win) {
             inputState.y,
             mouseEvent,
             win);
+        if (event.MouseButton.isSecondary(a.button)) {
+          let contextMenuEvent = Object.assign({},
+              mouseEvent, {type: "contextmenu"});
+          event.synthesizeMouseAtPoint(
+              inputState.x,
+              inputState.y,
+              contextMenuEvent,
+              win);
+        }
         break;
 
       case action.PointerType.Pen:
diff --git a/testing/marionette/event.js b/testing/marionette/event.js
index 804c57c59db1..b3b4a7082cb4 100644
--- a/testing/marionette/event.js
+++ b/testing/marionette/event.js
@@ -57,6 +57,18 @@ event.Modifiers = {
   metaKey: 3,
 };
 
+event.MouseButton = {
+  isPrimary(button) {
+    return button === 0;
+  },
+  isAuxiliary(button) {
+    return button === 1;
+  },
+  isSecondary(button) {
+    return button === 2;
+  },
+};
+
 /**
  * Sends a mouse event to given target.
  *
diff --git a/testing/web-platform/tests/webdriver/tests/actions/mouse.py b/testing/web-platform/tests/webdriver/tests/actions/mouse.py
index 5ddcef4baa38..3ff1e3eb5a79 100644
--- a/testing/web-platform/tests/webdriver/tests/actions/mouse.py
+++ b/testing/web-platform/tests/webdriver/tests/actions/mouse.py
@@ -50,6 +50,30 @@ def test_click_at_coordinates(session, test_actions_page, mouse_chain):
     assert expected == filtered_events[1:]
 
 
+def test_context_menu_at_coordinates(session, test_actions_page, mouse_chain):
+    div_point = {
+        "x": 82,
+        "y": 187,
+    }
+    mouse_chain \
+        .pointer_move(div_point["x"], div_point["y"]) \
+        .pointer_down(button=2) \
+        .pointer_up(button=2) \
+        .perform()
+    events = get_events(session)
+    expected = [
+        {"type": "mousedown", "button": 2},
+        {"type": "contextmenu",  "button": 2},
+    ]
+    assert len(events) == 4
+    filtered_events = [filter_dict(e, expected[0]) for e in events]
+    mousedown_contextmenu_events = [
+        x for x in filtered_events
+        if x["type"] in ["mousedown", "contextmenu"]
+    ]
+    assert expected == mousedown_contextmenu_events
+
+
 def test_click_element_center(session, test_actions_page, mouse_chain):
     outer = session.find.css("#outer", all=False)
     center = get_center(outer.rect)
diff --git a/testing/web-platform/tests/webdriver/tests/actions/support/test_actions_wdspec.html b/testing/web-platform/tests/webdriver/tests/actions/support/test_actions_wdspec.html
index c3d6d12daa02..be273229a3b4 100644
--- a/testing/web-platform/tests/webdriver/tests/actions/support/test_actions_wdspec.html
+++ b/testing/web-platform/tests/webdriver/tests/actions/support/test_actions_wdspec.html
@@ -64,6 +64,9 @@
         }
 
         function recordPointerEvent(event) {
+          if (event.type === "contextmenu") {
+            event.preventDefault();
+          }
           allEvents.events.push({
             "type": event.type,
             "button": event.button,