diff --git a/browser/devtools/framework/toolbox.js b/browser/devtools/framework/toolbox.js
index d07238f7129d..dbfe7239a54e 100644
--- a/browser/devtools/framework/toolbox.js
+++ b/browser/devtools/framework/toolbox.js
@@ -1223,6 +1223,7 @@ Toolbox.prototype = {
     if (this.target.isLocalTab) {
       this._requisition.destroy();
     }
+    this._telemetry.toolClosed("toolbox");
     this._telemetry.destroy();
 
     return this._destroyer = promise.all(outstanding).then(() => {
diff --git a/browser/devtools/shared/telemetry.js b/browser/devtools/shared/telemetry.js
index a2a3a0ffb345..b5832b3a368f 100644
--- a/browser/devtools/shared/telemetry.js
+++ b/browser/devtools/shared/telemetry.js
@@ -61,6 +61,8 @@ let {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
 Telemetry.prototype = {
   _histograms: {
     toolbox: {
+      histogram: "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN",
+      userHistogram: "DEVTOOLS_TOOLBOX_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_TOOLBOX_TIME_ACTIVE_SECONDS"
     },
     options: {
@@ -212,8 +214,6 @@ Telemetry.prototype = {
    */
   log: function(histogramId, value) {
     if (histogramId) {
-      let histogram;
-
       try {
         let histogram = Services.telemetry.getHistogramById(histogramId);
         histogram.add(value);
diff --git a/browser/devtools/shared/test/browser.ini b/browser/devtools/shared/test/browser.ini
index 158e1b5a112f..00e1362f7d4e 100644
--- a/browser/devtools/shared/test/browser.ini
+++ b/browser/devtools/shared/test/browser.ini
@@ -20,6 +20,7 @@ support-files =
 [browser_telemetry_button_scratchpad.js]
 [browser_telemetry_button_tilt.js]
 [browser_telemetry_sidebar.js]
+[browser_telemetry_toolbox.js]
 [browser_telemetry_toolboxtabs_inspector.js]
 [browser_telemetry_toolboxtabs_jsdebugger.js]
 [browser_telemetry_toolboxtabs_jsprofiler.js]
diff --git a/browser/devtools/shared/test/browser_telemetry_sidebar.js b/browser/devtools/shared/test/browser_telemetry_sidebar.js
index 381a8f5fc7e5..a3edf6b797e1 100644
--- a/browser/devtools/shared/test/browser_telemetry_sidebar.js
+++ b/browser/devtools/shared/test/browser_telemetry_sidebar.js
@@ -73,6 +73,8 @@ function checkResults() {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
+    } else if (histId === "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN") {
+      is(value.length, 1, histId + " has only one entry");
     } else if (histId.endsWith("OPENED_BOOLEAN")) {
       ok(value.length > 1, histId + " has more than one entry");
 
diff --git a/browser/devtools/shared/test/browser_telemetry_toolbox.js b/browser/devtools/shared/test/browser_telemetry_toolbox.js
new file mode 100644
index 000000000000..45c7ce45630d
--- /dev/null
+++ b/browser/devtools/shared/test/browser_telemetry_toolbox.js
@@ -0,0 +1,103 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const TEST_URI = "data:text/html;charset=utf-8,<p>browser_telemetry_toolbox.js</p>";
+
+// Because we need to gather stats for the period of time that a tool has been
+// opened we make use of setTimeout() to create tool active times.
+const TOOL_DELAY = 200;
+
+let {Promise: promise} = Cu.import("resource://gre/modules/commonjs/sdk/core/promise.js", {});
+let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
+let require = Cu.import("resource://gre/modules/devtools/Loader.jsm", {}).devtools.require;
+let Telemetry = require("devtools/shared/telemetry");
+
+function init() {
+  Telemetry.prototype.telemetryInfo = {};
+  Telemetry.prototype._oldlog = Telemetry.prototype.log;
+  Telemetry.prototype.log = function(histogramId, value) {
+    if (histogramId) {
+      if (!this.telemetryInfo[histogramId]) {
+        this.telemetryInfo[histogramId] = [];
+      }
+
+      this.telemetryInfo[histogramId].push(value);
+    }
+  };
+
+  openToolboxThreeTimes();
+}
+
+let pass = 0;
+function openToolboxThreeTimes() {
+  let target = TargetFactory.forTab(gBrowser.selectedTab);
+
+  gDevTools.showToolbox(target, "inspector").then(function(toolbox) {
+    info("Toolbox opened");
+
+    toolbox.once("destroyed", function() {
+      if (pass++ === 3) {
+        checkResults();
+      } else {
+        openToolboxThreeTimes();
+      }
+    });
+    // We use a timeout to check the toolbox's active time
+    setTimeout(function() {
+      gDevTools.closeToolbox(target);
+    }, TOOL_DELAY);
+  }).then(null, console.error);
+}
+
+function checkResults() {
+  let result = Telemetry.prototype.telemetryInfo;
+
+  for (let [histId, value] of Iterator(result)) {
+    if (histId.endsWith("OPENED_PER_USER_FLAG")) {
+      ok(value.length === 1 && value[0] === true,
+         "Per user value " + histId + " has a single value of true");
+    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+      ok(value.length > 1, histId + " has more than one entry");
+
+      let okay = value.every(function(element) {
+        return element === true;
+      });
+
+      ok(okay, "All " + histId + " entries are === true");
+    } else if (histId.endsWith("TIME_ACTIVE_SECONDS")) {
+      ok(value.length > 1, histId + " has more than one entry");
+
+      let okay = value.every(function(element) {
+        return element > 0;
+      });
+
+      ok(okay, "All " + histId + " entries have time > 0");
+    }
+  }
+
+  finishUp();
+}
+
+function finishUp() {
+  gBrowser.removeCurrentTab();
+
+  Telemetry.prototype.log = Telemetry.prototype._oldlog;
+  delete Telemetry.prototype._oldlog;
+  delete Telemetry.prototype.telemetryInfo;
+
+  TargetFactory = Services = promise = require = null;
+
+  finish();
+}
+
+function test() {
+  waitForExplicitFinish();
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.selectedBrowser.addEventListener("load", function() {
+    gBrowser.selectedBrowser.removeEventListener("load", arguments.callee, true);
+    waitForFocus(init, content);
+  }, true);
+
+  content.location = TEST_URI;
+}
diff --git a/toolkit/components/telemetry/Histograms.json b/toolkit/components/telemetry/Histograms.json
index c39115f020ea..061990e78a99 100644
--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -5392,6 +5392,11 @@
     "n_buckets": "1000",
     "description": "The time (in milliseconds) that it took an 'assign' request to go round trip."
   },
+  "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN": {
+    "expires_in_version": "never",
+    "kind": "boolean",
+    "description": "How many times has the devtool's toolbox been opened?"
+  },
   "DEVTOOLS_OPTIONS_OPENED_BOOLEAN": {
     "expires_in_version": "never",
     "kind": "boolean",
@@ -5492,6 +5497,11 @@
     "kind": "boolean",
     "description": "How many times has a custom developer tool been opened via the toolbox button?"
   },
+  "DEVTOOLS_TOOLBOX_OPENED_PER_USER_FLAG": {
+    "expires_in_version": "never",
+    "kind": "flag",
+    "description": "How many times has the devtool's toolbox been opened?"
+  },
   "DEVTOOLS_OPTIONS_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",