--- a/devtools/client/shared/test/browser.ini
+++ b/devtools/client/shared/test/browser.ini
@@ -141,16 +141,17 @@ skip-if = e10s # Bug 1221911, bug 122228
 [browser_html_tooltip_arrow-02.js]
 [browser_html_tooltip_consecutive-show.js]
 [browser_html_tooltip_hover.js]
 [browser_html_tooltip_offset.js]
 [browser_html_tooltip_rtl.js]
 [browser_html_tooltip_variable-height.js]
 [browser_html_tooltip_width-auto.js]
 [browser_html_tooltip_xul-wrapper.js]
+[browser_html_tooltip_zoom.js]
 [browser_inplace-editor-01.js]
 [browser_inplace-editor-02.js]
 [browser_inplace-editor_autoclose_parentheses.js]
 [browser_inplace-editor_autocomplete_01.js]
 [browser_inplace-editor_autocomplete_02.js]
 [browser_inplace-editor_autocomplete_offset.js]
 [browser_inplace-editor_autocomplete_css_variable.js]
 [browser_inplace-editor_maxwidth.js]

new file mode 100644
--- /dev/null
+++ b/devtools/client/shared/test/browser_html_tooltip_zoom.js
@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+/* import-globals-from helper_html_tooltip.js */
+
+"use strict";
+
+/**
+ * Test the HTMLTooltip is displayed correct position if content is zoomed in.
+ */
+
+const HTML_NS = "http://www.w3.org/1999/xhtml";
+const TEST_URI = CHROME_URL_ROOT + "doc_html_tooltip.xul";
+
+const {HTMLTooltip} = require("devtools/client/shared/widgets/tooltip/HTMLTooltip");
+
+function getTooltipContent(doc) {
+  let div = doc.createElementNS(HTML_NS, "div");
+  div.style.height = "50px";
+  div.style.boxSizing = "border-box";
+  div.style.backgroundColor = "red";
+  div.textContent = "tooltip";
+  return div;
+}
+
+add_task(async function() {
+  let [host,, doc] = await createHost("window", TEST_URI);
+  const zoom = 1.5;
+  await pushPref("devtools.toolbox.zoomValue", zoom.toString(10));
+
+  // Change this xul zoom to the x1.5 since this test doesn't use the toolbox preferences.
+  let contentViewer = host.frame.docShell.contentViewer;
+  contentViewer.fullZoom = zoom;
+  let tooltip = new HTMLTooltip(doc, {useXulWrapper: true});
+
+  info("Set tooltip content");
+  tooltip.setContent(getTooltipContent(doc), {width: 100, height: 50});
+
+  is(tooltip.isVisible(), false, "Tooltip is not visible");
+
+  info("Show the tooltip and check the expected events are fired.");
+  let onShown = tooltip.once("shown");
+  tooltip.show(doc.getElementById("box1"));
+  await onShown;
+
+  let menuRect =
+      doc.querySelector(".tooltip-xul-wrapper").getBoxQuads({relativeTo: doc})[0].bounds;
+  let anchorRect = doc.getElementById("box1").getBoxQuads({relativeTo: doc})[0].bounds;
+  let xDelta = Math.abs(menuRect.left - anchorRect.left);
+  let yDelta = Math.abs(menuRect.top - anchorRect.bottom);
+
+  // This test allow the rounded error and platform's offset.
+  // For detail, see the devtools/client/framework/test/browser_toolbox_zoom_popup.js
+  ok(xDelta < 2, "xDelta is lower than 2: " + xDelta + ".");
+  ok(yDelta < 6, "yDelta is lower than 6: " + yDelta + ".");
+
+  info("Hide the tooltip and check the expected events are fired.");
+
+  let onPopupHidden = tooltip.once("hidden");
+  tooltip.hide();
+  await onPopupHidden;
+
+  tooltip.destroy();
+  await host.destroy();
+});

--- a/devtools/client/shared/widgets/tooltip/HTMLTooltip.js
+++ b/devtools/client/shared/widgets/tooltip/HTMLTooltip.js
@@ -4,16 +4,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const EventEmitter = require("devtools/shared/event-emitter");
 const {TooltipToggle} = require("devtools/client/shared/widgets/tooltip/TooltipToggle");
 const {listenOnce} = require("devtools/shared/async-utils");
+const Services = require("Services");
 
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 
 const POSITION = {
   TOP: "top",
   BOTTOM: "bottom",
 };
@@ -593,17 +594,21 @@ HTMLTooltip.prototype = {
     panel.setAttribute("class", "tooltip-xul-wrapper");
 
     return panel;
   },
 
   _showXulWrapperAt: function(left, top) {
     this.xulPanelWrapper.addEventListener("popuphidden", this._onXulPanelHidden);
     let onPanelShown = listenOnce(this.xulPanelWrapper, "popupshown");
-    this.xulPanelWrapper.openPopupAtScreen(left, top, false);
+    let zoom = parseFloat(Services.prefs.getCharPref("devtools.toolbox.zoomValue"));
+    if (!zoom || isNaN(zoom)) {
+      zoom = 1.0;
+    }
+    this.xulPanelWrapper.openPopupAtScreen(left * zoom, top * zoom, false);
     return onPanelShown;
   },
 
   _hideXulWrapper: function() {
     this.xulPanelWrapper.removeEventListener("popuphidden", this._onXulPanelHidden);
 
     if (this.xulPanelWrapper.state === "closed") {
       // XUL panel is already closed, resolve immediately.