--- a/devtools/client/locales/en-US/webconsole.properties
+++ b/devtools/client/locales/en-US/webconsole.properties
@@ -30,16 +30,21 @@ webConsoleMoreInfoLabel=Learn More
 # anonymous. Test console.trace() in the webconsole.
 stacktrace.anonymousFunction=<anonymous>
 
 # LOCALIZATION NOTE (stacktrace.asyncStack): this string is used to
 # indicate that a given stack frame has an async parent.
 # %S is the "Async Cause" of the frame.
 stacktrace.asyncStack=(Async: %S)
 
+# LOCALIZATION NOTE (timeLog): this string is used to display the result of
+# the console.timeLog() call. Parameters: %1$S is the name of the timer, %2$S
+# is the number of milliseconds.
+timeLog=%1$S: %2$Sms
+
 # LOCALIZATION NOTE (timeEnd): this string is used to display the result of
 # the console.timeEnd() call. Parameters: %1$S is the name of the timer, %2$S
 # is the number of milliseconds.
 timeEnd=%1$S: %2$Sms
 
 # LOCALIZATION NOTE (consoleCleared): this string is displayed when receiving a
 # call to console.clear() to let the user know the previous messages of the
 # console have been removed programmatically.

--- a/devtools/client/webconsole/test/components/console-api-call.test.js
+++ b/devtools/client/webconsole/test/components/console-api-call.test.js
@@ -234,26 +234,47 @@ describe("ConsoleAPICall component:", ()
     it("shows an error if called again", () => {
       const message = stubPreparedMessages.get("timerAlreadyExists");
       const wrapper = render(ConsoleApiCall({ message, serviceContainer }));
 
       expect(wrapper.find(".message-body").text()).toBe("Timer “bar” already exists.");
     });
   });
 
+  describe("console.timeLog", () => {
+    it("renders as expected", () => {
+      let message = stubPreparedMessages.get("console.timeLog('bar') - 1");
+      let wrapper = render(ConsoleApiCall({ message, serviceContainer }));
+
+      expect(wrapper.find(".message-body").text()).toBe(message.parameters[0]);
+      expect(wrapper.find(".message-body").text()).toMatch(/^bar: \d+(\.\d+)?ms$/);
+
+      message = stubPreparedMessages.get("console.timeLog('bar') - 2");
+      wrapper = render(ConsoleApiCall({ message, serviceContainer }));
+      expect(wrapper.find(".message-body").text())
+        .toMatch(/^bar: \d+(\.\d+)?ms second call Object \{ state\: 1 \}$/);
+    });
+    it("shows an error if the timer doesn't exist", () => {
+      const message = stubPreparedMessages.get("timeLog.timerDoesntExist");
+      const wrapper = render(ConsoleApiCall({ message, serviceContainer }));
+
+      expect(wrapper.find(".message-body").text()).toBe("Timer “bar” doesn’t exist.");
+    });
+  });
+
   describe("console.timeEnd", () => {
     it("renders as expected", () => {
       const message = stubPreparedMessages.get("console.timeEnd('bar')");
       const wrapper = render(ConsoleApiCall({ message, serviceContainer }));
 
       expect(wrapper.find(".message-body").text()).toBe(message.messageText);
       expect(wrapper.find(".message-body").text()).toMatch(/^bar: \d+(\.\d+)?ms$/);
     });
     it("shows an error if the timer doesn't exist", () => {
-      const message = stubPreparedMessages.get("timerDoesntExist");
+      const message = stubPreparedMessages.get("timeEnd.timerDoesntExist");
       const wrapper = render(ConsoleApiCall({ message, serviceContainer }));
 
       expect(wrapper.find(".message-body").text()).toBe("Timer “bar” doesn’t exist.");
     });
   });
 
   describe("console.trace", () => {
     it("renders", () => {

--- a/devtools/client/webconsole/test/fixtures/stub-generators/head.js
+++ b/devtools/client/webconsole/test/fixtures/stub-generators/head.js
@@ -21,17 +21,18 @@ const { stubPackets } = require("devtool
 const {
   consoleApi,
   cssMessage,
   evaluationResult,
   networkEvent,
   pageError,
 } = require("devtools/client/webconsole/test/fixtures/stub-generators/stub-snippets.js");
 
-const BASE_PATH = "../../../devtools/client/webconsole/test/fixtures";
+const BASE_PATH = env.get("MOZ_DEVELOPER_REPO_DIR") +
+                  "/devtools/client/webconsole/test/fixtures";
 
 let cachedPackets = {};
 
 function getCleanedPacket(key, packet) {
   if (Object.keys(cachedPackets).includes(key)) {
     return cachedPackets[key];
   }
 
@@ -69,17 +70,17 @@ function getCleanedPacket(key, packet) {
       res.actor = existingPacket.actor;
     }
 
     if (res.message) {
       // Clean timeStamp on the message prop.
       res.message.timeStamp = existingPacket.message.timeStamp;
       if (res.message.timer) {
         // Clean timer properties on the message.
-        // Those properties are found on console.time and console.timeEnd calls,
+        // Those properties are found on console.time, timeLog and timeEnd calls,
         // and those time can vary, which is why we need to clean them.
         if ("duration" in res.message.timer) {
           res.message.timer.duration = existingPacket.message.timer.duration;
         }
       }
 
       if (Array.isArray(res.message.arguments)) {
         res.message.arguments = res.message.arguments.map((argument, i) => {

--- a/devtools/client/webconsole/test/fixtures/stub-generators/stub-snippets.js
+++ b/devtools/client/webconsole/test/fixtures/stub-generators/stub-snippets.js
@@ -54,23 +54,33 @@ function testStacktraceFiltering() {
 function foo() {
   testStacktraceFiltering()
 }
 
 foo()
 `});
 
 consoleApi.set("console.time('bar')", {
-  keys: ["console.time('bar')", "timerAlreadyExists",
-         "console.timeEnd('bar')", "timerDoesntExist"],
+  keys: [
+    "console.time('bar')",
+    "timerAlreadyExists",
+    "console.timeLog('bar') - 1",
+    "console.timeLog('bar') - 2",
+    "console.timeEnd('bar')",
+    "timeEnd.timerDoesntExist",
+    "timeLog.timerDoesntExist",
+  ],
   code: `
 console.time("bar");
 console.time("bar");
+console.timeLog("bar");
+console.timeLog("bar", "second call", {state: 1});
 console.timeEnd("bar");
 console.timeEnd("bar");
+console.timeLog("bar");
 `});
 
 consoleApi.set("console.table('bar')", {
   keys: ["console.table('bar')"],
   code: `
 console.table('bar');
 `});
 

--- a/devtools/client/webconsole/test/fixtures/stubs/consoleApi.js
+++ b/devtools/client/webconsole/test/fixtures/stubs/consoleApi.js
@@ -868,57 +868,164 @@ stubPreparedMessages.set(`timerAlreadyEx
   "exceptionDocURL": null,
   "userProvidedStyles": [],
   "notes": null,
   "indent": 0,
   "prefix": "",
   "private": false
 }));
 
-stubPreparedMessages.set(`console.timeEnd('bar')`, new ConsoleMessage({
+stubPreparedMessages.set(`console.timeLog('bar') - 1`, new ConsoleMessage({
   "id": "1",
   "allowRepeating": true,
   "source": "console-api",
-  "timeStamp": 1502884924759,
-  "type": "timeEnd",
+  "timeStamp": 1526920999996,
+  "type": "timeLog",
   "helperType": null,
   "level": "log",
-  "messageText": "bar: 1.21ms",
-  "parameters": null,
-  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":4,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"log\",\"messageText\":\"bar: 1.21ms\",\"parameters\":null,\"source\":\"console-api\",\"type\":\"timeEnd\",\"userProvidedStyles\":[],\"private\":false}",
+  "messageText": null,
+  "parameters": [
+    "bar: 1ms"
+  ],
+  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":4,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"log\",\"messageText\":null,\"parameters\":[\"bar: 1ms\"],\"source\":\"console-api\",\"type\":\"timeLog\",\"userProvidedStyles\":[],\"private\":false}",
   "stacktrace": null,
   "frame": {
     "source": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
     "line": 4,
     "column": 1
   },
   "groupId": null,
   "exceptionDocURL": null,
   "userProvidedStyles": [],
   "notes": null,
   "indent": 0,
   "prefix": "",
   "private": false
 }));
 
-stubPreparedMessages.set(`timerDoesntExist`, new ConsoleMessage({
+stubPreparedMessages.set(`console.timeLog('bar') - 2`, new ConsoleMessage({
+  "id": "1",
+  "allowRepeating": true,
+  "source": "console-api",
+  "timeStamp": 1526920999996,
+  "type": "timeLog",
+  "helperType": null,
+  "level": "log",
+  "messageText": null,
+  "parameters": [
+    "bar: 1ms",
+    "second call",
+    {
+      "type": "object",
+      "actor": "server1.conn0.child1/obj34",
+      "class": "Object",
+      "extensible": true,
+      "frozen": false,
+      "sealed": false,
+      "ownPropertyLength": 1,
+      "preview": {
+        "kind": "Object",
+        "ownProperties": {
+          "state": {
+            "configurable": true,
+            "enumerable": true,
+            "writable": true,
+            "value": 1
+          }
+        },
+        "ownSymbols": [],
+        "ownPropertiesLength": 1,
+        "ownSymbolsLength": 0,
+        "safeGetterValues": {}
+      }
+    }
+  ],
+  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":5,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"log\",\"messageText\":null,\"parameters\":[\"bar: 1ms\",\"second call\",{\"type\":\"object\",\"actor\":\"server1.conn0.child1/obj34\",\"class\":\"Object\",\"extensible\":true,\"frozen\":false,\"sealed\":false,\"ownPropertyLength\":1,\"preview\":{\"kind\":\"Object\",\"ownProperties\":{\"state\":{\"configurable\":true,\"enumerable\":true,\"writable\":true,\"value\":1}},\"ownSymbols\":[],\"ownPropertiesLength\":1,\"ownSymbolsLength\":0,\"safeGetterValues\":{}}}],\"source\":\"console-api\",\"type\":\"timeLog\",\"userProvidedStyles\":[],\"private\":false}",
+  "stacktrace": null,
+  "frame": {
+    "source": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "line": 5,
+    "column": 1
+  },
+  "groupId": null,
+  "exceptionDocURL": null,
+  "userProvidedStyles": [],
+  "notes": null,
+  "indent": 0,
+  "prefix": "",
+  "private": false
+}));
+
+stubPreparedMessages.set(`console.timeEnd('bar')`, new ConsoleMessage({
   "id": "1",
   "allowRepeating": true,
   "source": "console-api",
   "timeStamp": 1502884924759,
   "type": "timeEnd",
   "helperType": null,
+  "level": "log",
+  "messageText": "bar: 1.21ms",
+  "parameters": null,
+  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":6,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"log\",\"messageText\":\"bar: 1.21ms\",\"parameters\":null,\"source\":\"console-api\",\"type\":\"timeEnd\",\"userProvidedStyles\":[],\"private\":false}",
+  "stacktrace": null,
+  "frame": {
+    "source": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "line": 6,
+    "column": 1
+  },
+  "groupId": null,
+  "exceptionDocURL": null,
+  "userProvidedStyles": [],
+  "notes": null,
+  "indent": 0,
+  "prefix": "",
+  "private": false
+}));
+
+stubPreparedMessages.set(`timeEnd.timerDoesntExist`, new ConsoleMessage({
+  "id": "1",
+  "allowRepeating": true,
+  "source": "console-api",
+  "timeStamp": 1526920999998,
+  "type": "timeEnd",
+  "helperType": null,
   "level": "warn",
   "messageText": "Timer “bar” doesn’t exist.",
   "parameters": null,
-  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":5,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"warn\",\"messageText\":\"Timer “bar” doesn’t exist.\",\"parameters\":null,\"source\":\"console-api\",\"type\":\"timeEnd\",\"userProvidedStyles\":[],\"private\":false}",
+  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":7,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"warn\",\"messageText\":\"Timer “bar” doesn’t exist.\",\"parameters\":null,\"source\":\"console-api\",\"type\":\"timeEnd\",\"userProvidedStyles\":[],\"private\":false}",
   "stacktrace": null,
   "frame": {
     "source": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
-    "line": 5,
+    "line": 7,
+    "column": 1
+  },
+  "groupId": null,
+  "exceptionDocURL": null,
+  "userProvidedStyles": [],
+  "notes": null,
+  "indent": 0,
+  "prefix": "",
+  "private": false
+}));
+
+stubPreparedMessages.set(`timeLog.timerDoesntExist`, new ConsoleMessage({
+  "id": "1",
+  "allowRepeating": true,
+  "source": "console-api",
+  "timeStamp": 1526920999999,
+  "type": "timeLog",
+  "helperType": null,
+  "level": "warn",
+  "messageText": "Timer “bar” doesn’t exist.",
+  "parameters": null,
+  "repeatId": "{\"frame\":{\"source\":\"http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html\",\"line\":8,\"column\":1},\"groupId\":null,\"indent\":0,\"level\":\"warn\",\"messageText\":\"Timer “bar” doesn’t exist.\",\"parameters\":null,\"source\":\"console-api\",\"type\":\"timeLog\",\"userProvidedStyles\":[],\"private\":false}",
+  "stacktrace": null,
+  "frame": {
+    "source": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "line": 8,
     "column": 1
   },
   "groupId": null,
   "exceptionDocURL": null,
   "userProvidedStyles": [],
   "notes": null,
   "indent": 0,
   "prefix": "",
@@ -2419,62 +2526,171 @@ stubPackets.set(`timerAlreadyExists`, {
       "name": "bar"
     },
     "workerType": "none",
     "styles": [],
     "category": "webdev"
   }
 });
 
+stubPackets.set(`console.timeLog('bar') - 1`, {
+  "from": "server1.conn0.child1/consoleActor2",
+  "type": "consoleAPICall",
+  "message": {
+    "addonId": "",
+    "arguments": [
+      "bar"
+    ],
+    "columnNumber": 1,
+    "counter": null,
+    "filename": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "functionName": "triggerPacket",
+    "groupName": "",
+    "level": "timeLog",
+    "lineNumber": 4,
+    "prefix": "",
+    "private": false,
+    "timeStamp": 1526920999996,
+    "timer": {
+      "duration": 1,
+      "name": "bar"
+    },
+    "workerType": "none",
+    "styles": [],
+    "category": "webdev"
+  }
+});
+
+stubPackets.set(`console.timeLog('bar') - 2`, {
+  "from": "server1.conn0.child1/consoleActor2",
+  "type": "consoleAPICall",
+  "message": {
+    "addonId": "",
+    "arguments": [
+      "bar",
+      "second call",
+      {
+        "type": "object",
+        "actor": "server1.conn0.child1/obj34",
+        "class": "Object",
+        "extensible": true,
+        "frozen": false,
+        "sealed": false,
+        "ownPropertyLength": 1,
+        "preview": {
+          "kind": "Object",
+          "ownProperties": {
+            "state": {
+              "configurable": true,
+              "enumerable": true,
+              "writable": true,
+              "value": 1
+            }
+          },
+          "ownSymbols": [],
+          "ownPropertiesLength": 1,
+          "ownSymbolsLength": 0,
+          "safeGetterValues": {}
+        }
+      }
+    ],
+    "columnNumber": 1,
+    "counter": null,
+    "filename": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "functionName": "triggerPacket",
+    "groupName": "",
+    "level": "timeLog",
+    "lineNumber": 5,
+    "prefix": "",
+    "private": false,
+    "timeStamp": 1526920999996,
+    "timer": {
+      "duration": 1,
+      "name": "bar"
+    },
+    "workerType": "none",
+    "styles": [],
+    "category": "webdev"
+  }
+});
+
 stubPackets.set(`console.timeEnd('bar')`, {
   "from": "server1.conn0.child1/consoleActor2",
   "type": "consoleAPICall",
   "message": {
     "addonId": "",
     "arguments": [
       "bar"
     ],
     "columnNumber": 1,
     "counter": null,
     "filename": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
     "functionName": "triggerPacket",
     "groupName": "",
     "level": "timeEnd",
-    "lineNumber": 4,
+    "lineNumber": 6,
     "prefix": "",
     "private": false,
     "timeStamp": 1502884924759,
     "timer": {
       "duration": 1.2149999999999181,
       "name": "bar"
     },
     "workerType": "none",
     "styles": [],
     "category": "webdev"
   }
 });
 
-stubPackets.set(`timerDoesntExist`, {
+stubPackets.set(`timeEnd.timerDoesntExist`, {
   "from": "server1.conn0.child1/consoleActor2",
   "type": "consoleAPICall",
   "message": {
     "addonId": "",
     "arguments": [
       "bar"
     ],
     "columnNumber": 1,
     "counter": null,
     "filename": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
     "functionName": "triggerPacket",
     "groupName": "",
     "level": "timeEnd",
-    "lineNumber": 5,
+    "lineNumber": 7,
     "prefix": "",
     "private": false,
-    "timeStamp": 1502884924759,
+    "timeStamp": 1526920999998,
+    "timer": {
+      "error": "timerDoesntExist",
+      "name": "bar"
+    },
+    "workerType": "none",
+    "styles": [],
+    "category": "webdev"
+  }
+});
+
+stubPackets.set(`timeLog.timerDoesntExist`, {
+  "from": "server1.conn0.child1/consoleActor2",
+  "type": "consoleAPICall",
+  "message": {
+    "addonId": "",
+    "arguments": [
+      "bar"
+    ],
+    "columnNumber": 1,
+    "counter": null,
+    "filename": "http://example.com/browser/devtools/client/webconsole/test/fixtures/stub-generators/test-console-api.html",
+    "functionName": "triggerPacket",
+    "groupName": "",
+    "level": "timeLog",
+    "lineNumber": 8,
+    "prefix": "",
+    "private": false,
+    "timeStamp": 1526920999999,
     "timer": {
       "error": "timerDoesntExist",
       "name": "bar"
     },
     "workerType": "none",
     "styles": [],
     "category": "webdev"
   }

--- a/devtools/client/webconsole/utils/messages.js
+++ b/devtools/client/webconsole/utils/messages.js
@@ -101,26 +101,36 @@ function transformConsoleAPICallPacket(p
       if (timer && timer.error) {
         messageText = l10n.getFormatStr(timer.error, [timer.name]);
         level = MESSAGE_LEVEL.WARN;
       } else {
         // We don't show anything for console.time calls to match Chrome's behaviour.
         type = MESSAGE_TYPE.NULL_MESSAGE;
       }
       break;
+    case "timeLog":
     case "timeEnd":
-      parameters = null;
       if (timer && timer.error) {
+        parameters = null;
         messageText = l10n.getFormatStr(timer.error, [timer.name]);
         level = MESSAGE_LEVEL.WARN;
       } else if (timer) {
-        // We show the duration to users when calls console.timeEnd() is called,
+        // We show the duration to users when calls console.timeLog/timeEnd is called,
         // if corresponding console.time() was called before.
         let duration = Math.round(timer.duration * 100) / 100;
-        messageText = l10n.getFormatStr("timeEnd", [timer.name, duration]);
+        if (type === "timeEnd") {
+          messageText = l10n.getFormatStr("timeEnd", [timer.name, duration]);
+          parameters = null;
+        } else if (type === "timeLog") {
+          const [, ...rest] = parameters;
+          parameters = [
+            l10n.getFormatStr("timeLog", [timer.name, duration]),
+            ...rest,
+          ];
+        }
       } else {
         // If the `timer` property does not exists, we don't output anything.
         type = MESSAGE_TYPE.NULL_MESSAGE;
       }
       break;
     case "table":
       const supportedClasses = [
         "Array", "Object", "Map", "Set", "WeakMap", "WeakSet"];